I had a similar issue and it took a fair amount of work to first be able to reliably reproduce it and to convince NT scripting support team that it was an issue with the platform and not my code.
In my case, it had to do with processing orderflow data (ie; ticks, bid/ask, etc) and the other indicator was one of NT’s Orderflow+ tools. Adding the NT indicator on another chart in the same workspace caused my script to behave differently. I discovered that adding the NT indicator was causing the internal data series in my script to duplicate tick data - ie; each tick was presented to the script twice instead of once.
To make things even more complicated, it was also data source specific. NT team was unable to reproduce on their end with my exact steps because they used a different data source internally while I used Kinetick. After they switched to Kinetick, they were finally able to reproduce.
I don’t believe it has been addressed as of yet, but I gave up waiting and added work around in my own work to handle the goofy behavior.