adding a fusion node lower the resolution after relink to 4k

hi,
the title may feel a bit complicated so here is my issue:

I have a timeline with a 2k dnxhr444 master of a 35mm movie which I started cleaning with the fusion paint tool.
I was provided afterward a 4k dnxhrHQ master of that same movie.
I changed the timeline resolution to 4k, relinked the 2k master to the 4k one, with no issue, paint tool effect are still there and working and everything seems to be working fine except the metadata of the file which still show a 2k resolution while the codec itself has changed(dnxhr444 perviously and now dnxhrHQ) and i can verify this is actually the 4k master. so its just a metadata issue so far.

I detected the problem much later when hitting shift+D in the color page as the sharpen of the video would be better with everything bypassed.
after investigation it appears clip with a fusion paint node(even empty node) will have a visible lower resolution than without.
with a fusion node doing nothing :

with no fusion node :

I chose a text image as it shows the issue better.

I checked a backup of the project with the 2k master and there is no such issue.

thus I think the problem may come from the 4k files having been relinked from a 2k files and fusion processing it as 2k.

is there a way to force the file to 4k in the metadata or to fusion?



PS:(more info)
clip has the same name as the 2k file for conformation purpose, thus "2k" in its name
clip in bin:


clip from media pool:




project setup:

and also,
using "replace clip" rather than relink solve the issue but then I loose all my work on fusion for some reason I dont understand...