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You've run into +/- tolerances.
The Tele Vue is cut a bit larger and the filter a bit smaller.
Eyepieces vary in size (and by more than you would think), so a filter manufacturer would tend to want to cut the size a bit small in order to fit, say, 80% of all eyepieces easily.
Eyepiece manufacturers, on the other hand, would want to cut the threads a bit large so that 80% of all filters would fit.
Add manufacturing tolerances and you have a poor fit.
Here is what you can do, and it will help:
use a small model-painting brush to paint the bottom threads on the TV eyepiece flat black. This won't damage the eyepiece--one could even argue Tele Vue should have done that already. It will essentially reduce the inside diameter of the eyepiece a tad.
And, hopefully, though the filter will be loose thereafter, it will snug up at the bottom of the threads to fit tight enough to stay on.
Many Korean filters (notably those from Orion in the US) have a slightly aberrant thread that doesn't thread in more than a thread or two.
But other filters have the usual threads--but, as you found, vary in size a bit.
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