balena Etcherpro - flashed SD cards have ext4 errors

We have balena etcherpro (running 1.14.3) and have been using it flash SD cards. It has recently started producing cards that fail to boot with ext4 file system errors.

We’ve tried rebooting it and flashing fewer (just 1) card at a time but the problem persists.

Are there any software updates or workarounds we can try?

It was working OK for a long time but seems to have developed this fault recently.