I'll see if i can find the case - my description was a bit hand-wavy because it was a while ago, and just drawing on memory -- not that your explanation couldn't be true, but I thought I exercised that possibility. For your part, you'll remain sceptical it wasn't the driving language when I tell you it was Tcl, which is indeed the origin of this "manifest type" we're discussing :)
I can't replicate atm, but I now think it had to do w scientific notation, not octal - so "1e234..." into a text column. And istr "strict" solving my problem, but...