Do you mean that the arrow head moves when you stretch the text hotspot?
If so that is happening to me using your object in 18, 19 and 20 – they are all working the same.
I don’t see any problems with GLOB or REQUEST in the master/parameter scripts.
Those you have used are allowed (although judging from my other posts I am no expert in this field!).
It seems to me the problem is with the 2D hotspots in that the one for the text position is altering the value for the arrow head.
I haven’t got time to dig into it in detail though just at the moment but hope this helps.
Versions 6.5 to 22
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision M6800 - i7 4700MQ @ 2.40GHz, 16GB RAM, AMD FirePro M6100 (2GB), Windows 7 64bit