If this only happens with this lens then it seems like it must be the lens. I'd send that in for repair/warranty visit.
I ran into this issue when I adapted my Sigma 150mm macro to the a6300. At the most inopportune times the link would be lost. Solved the problem by making a plate with appropriate shim that links the tripod collar to the camera base, thus stabilizing the interface with the contacts. Simple.
Depress the lens lock button, twist the lens (just a bit will do) and return to locked (listen/feel the click) and turn it back on. The f stop will reappear. I have had this issue especially with larger/heavier lenses on my a6300.
WOW! Thanks for these tips!
Interesting. I have been planning on picking up some modeling clay but in the mean time I glued a half peach pit to a stick which I hold in an alligator clip on a bracket (from Radio Shack 20-30 years ago, they had a gadget with magnifying glass and two clips on a set of adjustable rods). Then the fun part, fishing a bug out of the vodka and perching it on the peach pit trying for a natural look. Legs don't want to co-operate, sneezing is not allowed. Fun times. My lab jack (from China) is rather sloppy and I have not been using it since working out the alligator clip plan.
WOW! Thank you for all this effort and info. This will keep me occupied for infinity LOL! My next question was going to be how do you display the subject, you foresaw that and it's all here.
Thanks, I'll do that. I still have a KODAK Neutral grey card i can use.
My efforts with LED lights seem all to be a bit too greenish and I have a bit of a challenge getting good color. Your colors are great, how do you do it?