[Paine in the Neck]

Clean and lubricate.
The bolt release is not popping back up in place to hold the bolt.

This. I suspect a bit of gunk or grit.

[Blueflag]

Good point. I had disassembled it and cleaned after buying, but you are right - situations like this ARE usually due to dirt/gunk/lack of PROPER lube.

I have a .22 semi-auto rifle that is amazingly sensitive to a clean action. Pretty much all jams on ejection go away with a good ‘detailing’.