I sent someone like 34 images, but because there was only 20 allowed per message I had to split it up into 2 messages.
no problem.
In each message it let me send the message without any text.
no problem.
But when refreshing the page it shows the number of files in place of our subsequent 2 text messages, as you can see below.
I would suggest not allowing an empty message or fix the way you're handling this information about number of files.
just to be clear I never sent a message that said "14 files" and he never sent a message that said "20 files" our messages said other things, but the files data replaced them.