[pay / PoS] amount changes inadvertently when editing memo, space causes error

[openoms]

Reported in private, confirmed on pay.blink.sv:

We have a merchant who adds his cash register ticket numbers to the Blink payments. But I just noticed, when we add a note (memo), and write numbers there, the amount to be paid gets changed as well!

The workaround is to first add the note/memo and then change the amount to be paid. But, if you then click on Note again and for example delete the Note, or just delete the last number of the note, then the total amount gets deleted.

to reproduce:
add note: Test
add amount: 101
open note, delete last t (then there is "Tes")
result: amount changes from 101 to 10 (the last 1 gets deleted)

reproduce first scenario:
add amount: 101
add note: 202
result: amount changes from 101 to 101,202

reproduce different variant:
add amount: 101
add note: 202
change note from 202 to 2022 (add a 2)
amount changes from 101 to 1012

reproduce variant with characters in the Note:
add amount: 101
add note: EH 3456 (with the space)
amount changes into: NaN and cannot be changed if you click on it!