[iOS] Negative Balance & Withdraw From Pot Calculation

Issue:

Currently my balance is on -£6.35
If I go to withdraw £5 from my Pot it shows my balance as £1.35 instead of -£1.35.

Details to reproduce:
Follow steps above
OS:
iOS 12
Device:
iPhone X
App Version:
2.38.0 (but has happened for aaaageeesss)

Screenshots:

This problem has been reported here:

Although Monzo do seem to have trouble with negative balances elsewhere too: