FieldValue.increment causing Flutter crash - firebase

Question

static Future<void> updateBalanceAmount(
{int amount, String balanceId, String userId}) {
var updateBalance = _db
.document('account/$userId/balance/$balanceId')
.updateData({'balance_amount': amount});
return updateBalance;
}
static Future<void> addCreditAmount(
{int amount, String balanceId, String userId}) async {
final DocumentReference ref = _db.document('account/$userId/balance/$balanceId');
await ref.updateData(<String, dynamic> {
'balance_amount': FieldValue.increment(amount),
});
}
Can someone explain why the top function works while the bottom function crashes? Specifically, I need to implement FieldValue.increment in Flutter but it consistently crashes when I try.
Here is the stack trace:
/libc (18226): Fatal signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x8 in tid 18285 (1.raster), pid 18226 (app.matto.com)
Build fingerprint: 'google/sdk_gphone_x86_arm/generic_x86_arm:11/RSR1.200819.001.A1/6823625:userdebug/dev-keys'
Revision: '0'
ABI: 'x86'
Timestamp: 2021-02-18 10:11:50-0500
pid: 18226, tid: 18285, name: 1.raster >>> app.matto.com <<<
uid: 10153
signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x8
Cause: null pointer dereference
eax 00000000 ebx c33c4920 ecx fffffff9 edx 00000000
edi 00000004 esi 00000000
ebp c158a648 esp c158a648 eip c2d12de5
backtrace:
#00 pc 013cbde5 /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#01 pc 013e4673 /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#02 pc 0146c58e /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#03 pc 0163fad3 /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#04 pc 0163f9a5 /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#05 pc 0163fe93 /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#06 pc 0163fc7f /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#07 pc 011f53b5 /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#08 pc 011f600a /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#09 pc 011f6e32 /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#10 pc 011a3f9b /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#11 pc 011f58e4 /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#12 pc 011f564c /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#13 pc 0120376f /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#14 pc 011aa38f /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#15 pc 011acee5 /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#16 pc 011acdf6 /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#17 pc 011b357e /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#18 pc 011b35ac /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#19 pc 00019337 /system/lib/libutils.so (android::SimpleLooperCallback::handleEvent(int, int, void*)+39) (BuildId: ab4be013cda31e8c45d48aa23a89d0f8)
#20 pc 0001a367 /system/lib/libutils.so (android::Looper::pollInner(int)+1127) (BuildId: ab4be013cda31e8c45d48aa23a89d0f8)
#21 pc 00019e96 /system/lib/libutils.so (android::Looper::pollOnce(int, int*, int*, void**)+118) (BuildId: ab4be013cda31e8c45d48aa23a89d0f8)
#22 pc 000133f5 /system/lib/libandroid.so (ALooper_pollOnce+101) (BuildId: f98006d4d736575082b552ff24b66f6c)
#23 pc 011b34bb /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#24 pc 011acda4 /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#25 pc 011ac8fc /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#26 pc 011b0a2d /data/app/~~qml9am1bePmidpLuDa7Bmg==/app.matto.com-mJtCM3HEUFtPk_pMu3CaCA==/lib/x86/libflutter.so (BuildId: 1c148fb28fc7334c78622f67843cff2825d62c72)
#27 pc 000e6964 /apex/com.android.runtime/lib/bionic/libc.so (__pthread_start(void*)+100) (BuildId: a690ed60a8b6a282b41dd991389b5fdb)
#28 pc 00078567 /apex/com.android.runtime/lib/bionic/libc.so (__start_thread+71) (BuildId: a690ed60a8b6a282b41dd991389b5fdb)