Könnte das damit zusammenhängen?
Die Stichwörter sind alle da:
https://docwiki.embarcadero.com/RADS...y_Improvements
Zitat:
The hidden "high bound" parameter type for an open array parameter was changed from Integer to NativeInt, an alias of Integer or Int64, depending on the target CPU. This means that Length, High, and Low for open array parameters in 64-bit compilers now return 64-bit value.