I am using the below RTB 22LR receiver with my CMMG dedicated bolt.
Been wondering if the port is too small; potentially causing ejection problems?  

The upper runs fairly reliable, and have been dismissing FTE's as what comes with the territory with 22LR's.

https://www.righttobear.com/rtb-9mm-22lr-true-slick-side-upper-receiver-rtb-pcc-3/

I actually prefer the 5.56 upper receiver with the dust cover.

That thing looks problematic

I have two uppers built on standard receivers and both run flawlessly.

Looks like more than enough room for proper ejection. Could be that your extractor doesn't hold the extracted case securely enough against the bolt face for the ejector to do its best work.

I just built with their 100% slick side upper and a CMMG barrel and bolt, but haven't tested it yet. Hopefully soon!

Cool...having a great time with mine.  I did have to use a reduced power hammer spring to get it to cycle reliably FYI.

Couple other things I noticed was that the kit ran better with a lower that has a tighter fit on the magazine.
What I mean is I have an old bushmaster lower that does not drop steel USGI mags freely.
When I had the upper on a lower where the CMMG magazine was a bit wobbly; i handed it to my friend to shoot, saw him use his support hand on the magwell...and the rifle proceeded to jam quite a bit.

Oh, one last observation....i usually load up 20 rounds max (being lazy)...and it has run just fine.
Loaded the CMMG mag maxed out (25?)...and both mags caused malfunctions at a local 3 gun match; which is currently allowing 22LR on some stages.
Next few stages, i loaded 20 rounds....not issues.

What is the length of the barrel on the upper?  What ammo are you shooting?  What hammer spring is in your lower?  Suppressed or not?  How new (i.e., how many rounds fired) is the .22 recoil spring?  Any extra weight added? Does the magazine sit at a proper height? Does the problem present itself early on or after a lot of shooting?
As has been noted, the ejection port is adequately sized.  Most likely, the rearward bolt velocity is too low to adequately "kick" the casing out.  Weak ammo, short (and unsuppressed) barrel, stiff hammer spring, stiff recoil spring, excess added weight to the bolt/recoil assembly, bolt drag on the bullet at the top of the mag, and/or a dirty chamber and/or extractor slot, alone or in combination, are at least some things that can lead to slower than desirable rearward bolt velocity.

Disclaimer:  I have no affiliation with or financial interest in any vendor or manufacturer; and I am not a competitive shooter or a blogger who receives any form of compensation for endorsements or favorable public or private comments.  Use of vendor and/or product brand names, if any, is for informational purposes only.

Best of luck.
MHO, YMMV, etc.  Be well.

SecondAmend,

Hello; i am running a 4.5 inch barrel (CMMG dedicated bolt combo).
I have been shooting winchester western previously, but have been shooting CCI mini mag recently.
Am using a reduced power ALG hammer spring in it.
The magazine should be at the correct height....using CMMG's that came with the combo.
Don't have any weights added and am running the factory recoil spring.
I think I have at least 500 rounds through it.
Have been running half and full configuration of the Rugged Oculus...it runs near problem free with the full configuration.

Last time out, I ran it in half suppressor length.
Two magazines loaded to 25 rounds, and two loaded to 20 rounds.
With the full magazines, i had a FTE on the 1st of 25 rounds.
With the magazines loaded to 20 rounds, it ran fine.

Next time out I am going to try running the suppressor in full length and test some more with mags loaded to 25 and 20 rounds.

I also have a spare standard AR receiver i would like to try out as well.

Sounds like your right at the edge of having enough kinetic energy from the ammo to get the bolt velocity needed.  The tips under "AR15/M16.22 Conversion Modifications" here may help get your system over the hump:
http://bazookabrothers.com/pages/technical+assistance/3

Also, some sources suggest clipping a few recoil spring coils.  I do not as the recoil spring will naturally soften somewhat as more rounds are fired; and with clipped coils, the spring can then be too soft.  An overly soft recoil spring can cause the bolt to hit the rear back plate too hard causing noise and potentially breaking the weld that connects the back plate and frame.

MHO, YMMV, etc. Good luck.  Be well.

RTB slick side, 4.5" CMMG barrel and bolt, BB weight, FA Binary FCG (lower weight springs). Load 22 rounds in CMMG/RTB mags (works out well for binary use), runs like a Swiss watch, CCI Supressor, Standard Velocity, Hi Speed bulk pack, no worries.