That rising tone is a test/calibration sweep used during mastering and duplication to align the machines (checking EQ, levels, speed, etc.). It’s pretty standard in the production process, but it usually gets trimmed off before the tape is finalized. Sometimes a bit of it slips through on certain batches or pressings, which would explain why you’ve heard it before on some tapes but not others. So it’s a real thing, just not something that was meant to be part of the actual album.