sticking temperature gauge issue

[DesertBMW]

Yes I did fix the lose ground nut on the back but this is 3rd E30 that I have this issue. When car is first started, gauge will stay at cold and will require light tap on the dash then the gauge jumps from cold to normal and operates fine.
I did attempt to replace just the temp gauge inside the cluster and I get the same result. I tested all the traces on the cluster board and it all looks great.

Searched but I all I get is the lose nut issue.

Edit with Update:

Problem is with temp gauge itself. Needle inside is physically sticking to something. I did some gentle bending of the needle, now the gauge works all the time.

[dnguyen1963]

Take the board out and look at it under a magnifying glass for any broken solder.

[BruceJ]

mine does the same, thinking its more of a mechanical issue with the gauge

[Delta]

Mine does this as well. Remove the cluster and inspect for loose connections, cracks in solder joints, and double check that nut.