Thanks guys!
The strawed ejector was noticeably misaligned with the slot in the breech block--had to push a little harder to slide the breech block over the ejector. And, it's scuffed up pretty badly (see attached photo).
The replacement ejector seems to be properly aligned with the slot in the breech block. I took the pistol to the range and fired 18 rounds of WWB 115 gr. No issues, the ejector still looks good (see attached photos).
My current theory is the chipped, numbers-matching, breech block was just a hair out of alignment, or loose, causing the plum ejector that came with the gun (which I presume was fit to the gun) to break, then broke the SARCO ejector, and perhaps bent the strawed ejector, such that it wouldn't align with the replacement breech block I installed. Or, maybe just bad luck, as Don suggests.
If I continue to have issues, I'll update this thread. Likewise, I'll try to remember to update this thread if I experience no further ejector issues, after the pistol has more run time.