Yea, I probably just got deceived by that clamp you fitted, makes the filter look shorter (the earlier filters were shorter)
I wasnt commenting on the dirt.
BTW, Rotax dont recomend fitting any sort of retainer/safety to the filter but your choice of course and does no harm.
but next time you fit one hand tight, try removing by hand after an engine run.
I've never known one come lose.
The exhaust interference with the filter is common, I have to loosen that header every oil change. (I do oil and filter every 50 hours, even though I run Mogas)
Oh and that crappy torx head magnetic plug was superseded by a hex-bolt head type some time ago, they are much easier to remove without damage but rather expensive (Apologies I now see the Different mag plugs were already discussed)