For some reason Apple reversed Center and Right text alignment between x86 and arm (AppleSilicon) processors.
LXBeams 6.2.1 (18421.1) accounts for this uses the same text alignment as other LXSeries applications when running on Apple Silicon.
For plots created on older versions of LXBeams running on an Apple Silicon processor there is a new command, Format->Convert->Text Field->Reverse Right/Center Alignments, which will exchange the alignment of text fields (Right<->Center) to fix text field alignments that may be reversed.