Preview always loops

Regardless of the setting of the 'loop options' button in the Preview panel, playback of a RAM preview ALWAYS loops.

I'm on AE Beta 25.2.2x85

I was using AE in "dangerous mode" - that is I was working on a project with linked comps with PPro also open. I quit both AE and PPro, relaunched AE (but not PPro), opened the same project, and the issue has gone away. Looks like it might be related to the dreaded, longstanding CTI not moving issue: https://community.adobe.com/t5/after-effects-discussions/pti-and-cti-not-moving-on-preview/m-p/15100265#M260508