I’m awaiting an answer to a support request email that I sent this morning (GMT) but I don’t know how frequently these get answered and also the support forum is closed so here goes.
Something appears to have been broken with file uploads. If I upload this PDF:
concepto(abono) | cantidad(62.23).pdf
it is now renamed to
concepto(abono) - cantidad(62_23).pdf
which screws this part of my workflow. I have tried it on Safari and Chrome (MacOS Mojave).
I can thereafter rename the file attachments, so it doesn’t seem these are now deemed illegal characters.