Filemaker Go crashes when adding an autograph

I have a problem with FileMaker Go 18.0.3.325 (iPad, iOS 13.x). The app crashes when I adding an autograph to a container field using Insert from Device. Does anyone have a similar experience? I has worked fine, using older versions of FMGo. How does this function work anyway? Is it kind of interactive webviewer that is called using Javascript to capture the autograph and putting it back as a graphic into the container field? Claris' documentation is non-existing on these kind of topics.

NB on other occasions, I noticed that an 'interactive container field' is in fact a webviewer that interacts with the container storage, and FileMaker sometimes seems to get confused, so I guess this is happening here too. Should I check for some non-standard browsers on the iPad (it's a customer's iPad, not my own)? Any suggestions would be welcome!