Disc Numbering Glitches

has any one seen this

I have box sets where there are 2 tags, [Disc #] a standard one and [Disc] a custom tag . I am seeing examples where these 2 are concatenated a eg 3;DISC NAME in the Disc # tag despite its data type being integer

this visible in TagScanner and Tag’n’Rename both show it. I no longer have AS but would saving via AS cause this ?

It seems to be random so finding an example is tough

any ideas ?