@Justin
I think that to reproduce you need focus FX browser and insert insert via the TCP FX List,
If I make FX browser tab focused via the FX chain window, it works as expected;
https://i.imgur.com/SiWSTzz.gif
I was able to replicate in a portable install, here the reaper .ini file, brand new from a portable install but with the Show FX and Sends in TCP options toggle as on.
https://drive.google.com/file/d/14sj...ew?usp=sharing
--
reaper blog issue seems a bit different, but maybe it is related somehow.