When enabling "Run Construction Script in Sequencer" on a Blueprint Child Actor and having "Rerun Construction Scripts" turned on in Sequencer, the Child BP's properties become inaccessible in Sequencer.
This was reported and tested in 4.22.3 (CL-7053642). This was reproduced in 4.23 (CL-8386587) and 4.24 (CL-9551884)
Results: The skeletal mesh component of the blueprint with Run Construction Script in Sequencer enabled turns yellow/red and its properties become inaccessible.
Expected: The properties of the skeletal mesh component are accessible.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-81840 in the post.