When a BitmapTextureGL is reused, its internal values are reset (flags, internal texture, and content). But the FilterInfo variable is not, so the every time that BitmapTextureGL is painted it will use the the old filter, altering the result.
Created attachment 413946 [details] Patch
Good catch. Are there any existing tests failing? If so, please add a comment about it. If not, can you add a new test?
I think this will fix tests but on top pach attached to bug #215445. So, it will be covered by backdrop filter tests.
(In reply to Carlos Garcia Campos from comment #3) > I think this will fix tests but on top pach attached to bug #215445. So, it > will be covered by backdrop filter tests. Yes, this together with the fix to bug #215445 will fix several backdrop filter related bugs.
Committed r269765: <https://trac.webkit.org/changeset/269765> All reviewed patches have been landed. Closing bug and clearing flags on attachment 413946 [details].