It does look like 1.6 has broken something... (or it may just be a latent issue in my code). Unfortunately, I haven't had an active sub for a few months now, but once ESO goes b2p I will come back and get this fixed. If someone else figures this bug out, I can integrate the fix and update the add-on.
Combat Reticle is "officially" fixed - I just uploaded version 1.1.1 and everything should be working again with patch 6. Thanks for everyone's patience and the community effort working around this issue while I was away.
For any other devs that are curious, ZO changed the names of the reticle stealth eye and text controls - they are now: ZO_ReticleContainerStealthIconStealthEye and ZO_ReticleContainerStealthIconStealthText.
Of course, please let me know if you find anymore issues.