Issue with using a calculated value on an HTML attribute

We have a calculated value script that clears out an HTML attribute when a workitem is placed into specific states.

The issue we are seeing is that any time the script runs the built-in RTC function to render the text HTML safe runs converting the already converted text again, and again, and again. Needless to say this makes the visible text pretty horrific quickly.

Is there anything we can do to mitigate this outside of converting the attribute to plain text, disabling the script, or creating an extension?