Increased Fortify effect from placed dread banner not stacking with other sources

Hi! I have a champion in heist SC who uses the permanent fortify node from the ascendancy as well as stacks a lot of increased fortify effect on gear and passive tree:
20% from rampart wheel
30% (40% while stationary) from steadfast wheel
20% from the crusader suffix on helmet
20% from a lethal pride timeless jewel, granting 10% on 2 notables each

All in all, this gives me a total of 90% increased fort effect while moving and 100% while stationary. So far so good.
Now the way this used to interact with dread banner's fortify buff back in 3.7 and 3.8 (which is when i last used this mechanic) is that the inc fort effect value from dread banner resulting from the number of banner stages would stack with your inc fort effect value from gear and tree and you would see a fortify buff icon in the top left with a timer underneath replacing the 'permanent' fortify icon from the champion node.
I tested this today on my heist champion and it doesn't seem to work that way anymore: I would only get the timed fortify buff from dread banner replacing my 'permanent' one whenever i had enough banner stages for dread banner's inc fort effect value to be HIGHER than the inc fort effect on gear/tree, so at least 46 stages while moving, corresponding to 92% inc fort effect. In contrast, while stationary, i am not able to receive any buff from banner placement at all because, seemingly, the buff provided by dread banner (100% inc at 50 stages) is not 'strong enough' to override my permanent fortify buff (also 100% while stationary).

I'd really appreciate it if this could be looked into or alternatively any info on this being changed ever since 3.8 ! Thanks!

Bump to add some info on the issue from a reddit thread i discussed this problem in:

I fooled around with testing damage from shaper slams on another champ i had on standard with similar gear last night to further test the dread banner interaction. I didnt record any exact data, I only tried roughly comparing dmg taken with only perma fort, then with dropped banner at full stages while moving (so that the stronger fort instance from db WOULD take effect as described above) and while stationary (so that NO temporary fort buff would appear in the buff icons). My findings: This issue definitely does not seem to be restricted to a display bug. Whenever i would tank the slam (on a non-miss from shaper mind you) with dropped banner so that no timed fort buff would appear (i.e. while stationary at up to 50 banner stages or while moving at up to 45 stages), I indeed took very similar dmg amounts to tanking it w/o dread banner placed shortly before (down to about 1500-1800 out of 6700 hp with 6% phys mit from pantheon of solaris, a 39% less dmg taken perma fortify and no other significant mitigation). Only when dropping db with 46 or more stages while moving (so that a new timed buff would appear) would i take significantly less dmg from his slam (i think he got me to only 50% hp or a bit more). So it seems that once you manage to create a stronger instance of fortify than your permanent one, that instance will take effect and still inherit all inc fort effect from gear and tree as it normally should.

TLDR: it seems like if you're above a certain threshold of inc fort effect on gear/tree (namely 100% for 50 banner stages), dropping db for a stronger fortify is not currently possible at all!

Link to mentioned thread: https://www.reddit.com/r/pathofexile/comments/ju6h8z/increased_fortify_effect_from_placed_dread_banner/

Bump. Confirmed from my testing that this bug is real and it has a significant impact on fortify effect stacking builds.