The cat and the signpost, nine treatments between them, one thing changed at a time.
The cat, plain
No filter anywhere — it only fades and lifts. If this one breaks, filters are innocent and something else is going on.

The cat with its glow
The teal light, arriving with it. One filter, no blur term.

The cat, exactly as the site does it
The glow with a zero-width blur beside it. This is the live treatment — I expect this one to go white.

The cat, glow standing still
Same glow, but it never changes — only the fade and the lift travel. Asks whether it is the filter moving that breaks it, or the filter merely being there.

The cat, lit from behind
The drawing wears nothing; the light is a soft wash on a box behind it. The candidate repair — and the one where your eye matters most, because the glow no longer traces the outline.

The cat as the site does it, smaller file
Identical to three, but the drawing is 900 across instead of 2000. Asks whether the browser is simply running out of room.

The signpost, exactly as the site does it
The light coming up — brightness climbing from half to full. A different filter from the cat's, in a different module. I expect this one to go black.

The signpost, no brightness
The same arrival with the brightness taken out — it only fades up. The candidate repair, and it costs the "darkness departing" feeling, so this is a look decision as much as a fix.

The signpost as the site does it, smaller file
Identical to seven, at 900 across instead of 1076. The room question again, for the other drawing.

Nothing marked yet.