Theory Of Operation
The fabric of space-time is a sock. A used sock. It has holes in it, stinks in parts, but will stretch to fit.
Due to some experimental time-saving procedures at a General Electric dryer factory in the 40's, sock pairs have been splitting.
The sock is not misplaced, but instead had become a big problem for another timeline. Not our problem. Extra socks should be isolated and reported to your local temporal inference specialist.
A sock, stretched to the size of say, a Delorean, is seemingly transparent. Time is like this as well. Bits of time stretched to the point of implausibility will stretch in this fashion, seemingly transparent. Causing concern for the time traveller. Causing concern to time travellers. Causing concern for the time traveller. Repetitive, similar but different phrasing of identical descriptions can cause concerns among time travellers.
Thusly, instead of just stopping by a store in the 50s and picking up a brand-new Stratocaster, one must correct whatever errors and paradoxes your presence may cause. But, since all your corrective actions were actually in the past relative to where one starts, the corrections were completed by the time origin arrival.
It's a bit of a stretch.