Properly, I’ll not inform an extended story, how I debug, however come on to the bug talked about within the title. I tracked his existence right down to BASIC 2.0 as used within the VIC-20, C64 and the early PET/CBM collection and it appears, that it was by no means detected, documented or mounted.

It’s associated to momentary strings, the stack of descriptors for momentary strings, that has a measurement of three, and the so referred to as “rubbish assortment”, which in actuality doesn’t accumulate rubbish, however does a defragmentation of string storage.

Fixing an historic bug like this should be a weirdly satisfying expertise.