When you've had secondary profiles in the past, did you have their phone calls and SMS toggle on?
If so, and you have an incoming call, it is my understanding that the call is still handled by the owner profile, and the secondary user shows you the call details after because it has as access to call logs with that permission.
That seems to ring true with what I read here:
https://github.com/GrapheneOS/platform_frameworks_base/blob/0593f6d85a596c3a189be2d23cae05a26826599d/core/res/res/xml/config_user_types.xml#L39
And specifically the line:
<default-restrictions no_sms="true" no_outgoing_calls="true" />
</profile-type>
I don't think there is any public facing way to change that toggle in the OS. You'd have to make your own builds of GrapheneOS to be enable that.
Which would explain why, now with phone calls disabled for the secondary user profile, you are able to answer the phone call, but not view the logs.
Your secondary user profile is not answering the call, instead your owner profile is.
This means that there is no practical way to stop receiving incoming phone calls, other than turning off your phone or turning off the SIM. The dialler app has direct boot so can also receive phone calls BFU.
There's also a similar issue described on the issue tracker. The development team also confirm that this behavior is by design: https://github.com/GrapheneOS/os-issue-tracker/issues/2155
Hope that helps. As communicated in the GitHub issue, the GrapheneOS development team has no interest to change this behavior since carrier based calls are not recommended anyway.