Your answer got me thinking about my KeyChain. Hadn't developed code for awhile and found some dated certs, and the one you mentioned, duplicated. Cleaned it all up and set some to "trust" (including Apple Worldwide Developer Relations Certificate Authority) instead of use system defaults), and it works. That makes me wonder if you may have inadvertently fixed it doing something else and that changing the trust setting for the cert didn't really fix it. In any case, I think it's safe to say that one potential source of this problem is XCode stumbling over problems in certs in your key chain and, one should review all that and clean things up.

I opened a smaller project and I don't see the problem. Simply having the project I'm working open causes the CPU to shoot up to aforementioned level and stay that way (so far) indefinitely. I cleared derived data and build folder. Didn't resolve it.

Final note: After closing two of the three desktop full screen windows I had open from the release (13) version of XCode, the problem went away and never returned, even after opening a new full screen desktop window.

Putting watch into airplane mode doesn't work. I hope you don't mean the mac because I use a BT keyboard and trackpad.

OK, you have to disabled BT on Apple watch in the watch's setting app. Airplane mode from the control panel doesn't seem to do it.

6/17/21: Amazingly (and gratefully) this seems to have resolved it (after XCode restart)! Note: This is all pretty new high end fast equipment. The USB connection however is going to the back of a Pro Display XDR. It suddenly occurs to me it might be worth checking whether cabling directly to notebook would help. Perhaps there is some latency when going through the display's built-in USB-C ports? Configuration: iPhone 13 Pro Max (iOS 15.5) Macbook Pro M1 Max (macOS Monterey, 12.4)

ulimit -c unlimited, plus, codesigning with the entitlements shown worked for me on Monterey 12.4, for binary I created with gcc. I just added steps 4 and 5 to the target that builds the binary in my Makefile. Then and only then does the app coredump to /cores.

I'm having the same problem, running latest macOS on 14" MacBook Pro Max (other information posted to this thread). I'm having this problem with Instruments 14.0.1 (14A400). iPhone 14 Pro Max iOS 16.1

Seems like Gregor-Karl is right. .inlinePreservingOnlyWhiteSpace preserves the spacing, and highlights bold-marked text (e.g. text to emphasize), but it leaves, for example, the block quote markup indicators ">" unprocessed as though a literal part of the text.

Doesn't work for me. XCode, Version 14.3 (14E222b)