Issues with K3 & battery grip on bulb setting

I tried out my recently purchased 3rd party battery grip last night on some star trail shots (no good results as every exposure at least 1 car came diwn the country road😠 but found that after the exposure is finished the camera sticks on the image display screen.
Switching off it stays stuck it only moves when I remove the battery grip....
Tried with just the body no issues.
Is this a common issue with third party grips?
Or am I missing something?

have you done them without the grip using bulb?

After a long exposure doesn't it do a dark exposure (which effectively shuts the camera down) to deal with noise/dodgy pixels?

Yes to both..I have done without grip and no issues.
It goes dark but there is a countdown on top display after which image preview appears as normal...my problem is if I use the grip the preview won't go away...if I switch off camera it us still there when I power back up only way to clear is to physically remove the battery grip.
I am assuming it us some issue with compatability of 3rd party device with my K3.
Guess my question is dies this happen on the pentax grip?