I went through a similar issue with a DW CBOB 10mm back in 2010. Bought it used (across the internet), spent brass looked a lot like yours (not every round, but every 4th-5th round), prior owner said he "never noticed it".
Possible, but unlikely. In all these years I have seldom found any 10mm brass at the range...most 10mm shooters are handloaders (as am I) and being a handloader I found that condition infuriating and unacceptable.
Posted here-and-there and got a number of replies. It's been a while but IIRC DW said "extractor" and I changed and tweaked on it multiple times to no avail. (I was able to make the feeding worse LOL, but no effect on the condition of the spent brass.)
Finally ended up filing on the ejector, shortened it a bit (seems that they use a lengthened ejector) and shaped it to control the direction of the ejected brass. Took several tries to get it right but I still have the 1911 and no smashed brass.
If so, it seems that the slide is not closing on the brass (as I had initially thought, and that others have postulated), but the brass is being ejected early and banging the slide on the way out. That would explain the "no jamming" part. I will admit that the amount of damage strains credulity, but brass is soft, SS is hard and the brass is being ejected forcibly...until I have a better explanation, that's the one I'm sticking with.
Not sure if Tisas uses an extended ejector but I think it might be standard fare for 10mm 1911s. Don't remember how much I shortened it, might have been .040 and it might have been a bit more. I think I have some pics of other people's ejectors, and could take some of mine if it would help.
I don't know if it is bad form to post a link to another site, but if you pm me I will find and send one or more of the threads I posted back then.
It's a fun cartridge, don't give up on it too early.
Best regards, Rich in TX