I expierence exactly the same issue - I thought it might be linked to another issue I found in this community: 

But opening my document in a Chrome incognito window did not resolve it.

Chrome version: Version 126.0.6478.183 (Official Build) (64-bit)

Hi @drobertssea and @Yokie crossing the Channel, thanks for posting in the Lucid Community! I appreciate you both attempting to use this feature in an incognito window, as this helps me eliminate some potential causes.

The next thing I would recommend is connecting to a different network or disconnecting from your VPN (if applicable)? Sometimes account performance issues can be related to internet security or speed issues. Additionally, can you try using the UML markup in another Lucid document to see if the issue persists in multiple documents? 

If neither of these steps resolve the issue, can you please send a temporary Support PIN for your document? This will allow me to take a closer look at the issue you’re experiencing. For more information on generating a Support PIN, check out this Help Center article. I appreciate your help and patience!

Hi Amelia! I’m no longer able to reproduce this behavior, either in an existing doc or a new one. Either y’all fixed it or it was something transient. Thanks for your help.

Hi @drobertssea, thanks for following up! After taking a look on my end, it looks like it was a known bug in our system, but our development recently released a solution to fix it. I’m glad to hear it’s working as expected again! Please let me know if you have any further questions!