EOS R7 won't recognize Sigma 120-300mm F2.8

[JRichards2012]

I recently purchased a R7 with the purpose of pairing it with my Sigma 120-300mm F2.8 Sports.  However it will not recognize the lens. That lens works perfectly with my adapted R6. And the R7 works just fine with other adapted Sigma lenses. Yet refuses to recognize that Sigma lens that i purchased it for. I have cleaned the lens terminals, taken the battery out of the camera, and replaced.  It still will not work.  I updated the firmware to 1.6.0 as well. Nothing works. Any information on this would be greatly appreciated.  

[JRichards2012]

My Sigma 85mm f1.4 Art lens works fine on the R7. it's not on the list. 

[March411]

I had two Sigma lenses that are/were not listed that performed real well on my R6 Mk II and R50. The only challenge I had was the 18-300mm F3.5-6.3 DC MACRO OS HSM | C would not bump the R6 Mk II into crop mode automatically, I had to do it manually. My 17-70mm F2.8-4 DC Macro (OS) HSM | C worked perfectly. Canon support worked with me for a little over an hour trying to figure out the issue with the 18-300mm but we could never get it to work automatically.

It does seem a little hit and miss but all my Sigma lenses did work well on R bodies after firmware updates.