I cannot add fractional amounts

Hi,

I'm using moneybuster (0.1.2 from F-Droid.org) with a Nextlcoud (18.0.4 Stable channel)/Cospend (0.5.3) backend. When I try to add a new invoice with a practional (i.e. 4.50€) amount, I get the following error:

This happens using the usual keyboard and the usual separator ("." as it appears in the keyboard or "," as it appears later in the items list; I tried writing with both of them with no luck). Is this realted to moneybuster or is it on the other hand realted to Cospend app?

Thanks!

Edit: I forgot to say I can create the invoice in the web UI from Cospend with no issues and of course the project does exists.