It's not weird and its not exchange rate either. I think you're simply confusing total fund/balance with your net deposit.

Using your format:
@21.09.21, 10:48am
Total Fund: RM1,985.77
Earning: RM144.71
Total Deposit: RM 1985.77 - RM144.71 = RM 1841.06

@22.09.21, 5:45pm
Total Fund: RM2,264.09
Earning: RM123.02
Total Deposit = RM 2264.09 - RM 123.02 = RM 2141.07 (+RM300 From previous Total Deposit)

Haven't used the app in a while but I suspect there's a place where you can see net deposit rather than total fund. That should clear up your confusion.