Scanner not found by scanimage

I have a Fujitsu ScanSnap ix500 connected via USB. For approximately 1 year it worked pretty well with gscan2pdf. A couple of weeks ago, probably after upgrading some packages, it stopped working.

If I type scanimage -L immediately after plugging in the USB cable, then scanner is found:

device `fujitsu:ScanSnap iX500:1251809' is a FUJITSU ScanSnap iX500 scanner

But after a few more seconds the scanner is not found anymore.

Instead lsusb gives

Bus 002 Device 007: ID 04c5:132b Fujitsu, Ltd ScanSnap iX500

and ```sane-find-scanner says

found USB scanner (vendor=0x04c5 [Fujitsu], product=0x132b [ScanSnap iX500]) at libusb:002:007

Any suggestions? Thanks!