My child's e-visa not found at border control

We have travelled back into the UK twice in last 3 months from different port of entries. In both cases my son's e-visa (ILR) didn't show on the system at the UK border control. But my wife's and my daughter's have come through the system.

I can get the e-visa share codes for all three of them and I can clearly see all their status online.

My wife's and daughter's "Status" on the e-visa gov website shows as "Settled" while my son's "Status" is shown as "Dependant". I am guessing this is because we applied for his visa with my wife's application while my daughter was born later (hence had her own application).

The comment on my son's e-visa does state "There is no limit on how long you can stay in the UK."

I am guessing this is the discrepancy? (but I am not sure)

Any one here faced a similar issue or any advice on "fixing" this issue?

The border control officer at the airport (2nd time) asked us to contact UKVI. Both times they simply commented saying "may be its just slow coming through". Not sure what needs to come through though.
I did ask both times and they just asked me to "register on the online system multiple times if needed" which seems a bit wrong to be honest. I can get multiple share codes but not sure what that will achieve.

I did offer to provide the share code both times but they said it wasn't needed both times. First time the officer simply lets us all through and didn't bother with any more checks which was odd to be honest. Second time the officer checked my son's BRP card which expired in Dec 2024.

Any advice appreciated, getting a bit worried with the whole ordeal....

On digging deeper, I figured that the passport we used for his ILR application has expired now and he is travelling on a (re-)new passport.

I have gone ahead uploaded his new passport details which has also forced the online UKVI system to log on using his new passport (while in the past I was using his BRP card to log on).

I am not sure if this is the issue because on my wife's and daughter's account I can only see the (expired) BRP card details under the identity documents section and not their passports. So the system as a whole is not at all transparent.

Just posting it here in case someone else is facing a similar issue.... will test my theory very soon because we are travelling again. I will keep this thread updated to help others, but in meantime any help/advice from others here also appreciated.