CK II - [3.2.1 AZCE] Merchant republic with another merchant republic as vassal

[Astro-Boy]

One line summary of your issue
[3.2.1 AZCE] Merchant republic with another merchant republic as vassal

Game Version
3.2.1 AzCE

What expansions do you have installed?
All of the above

Do you have mods enabled?
No

Please explain your issue is in as much detail as possible.
As a merchant republic, formed an independence faction and invited another merchant republic to it. After going to war, I am now a doge with a doge as vassal, which the republic UI doesn't handle especially well.

Steps to reproduce the issue.
The simplest repro steps are to start as either Amalfi or Ragusa (both merchant republics under the Byzantine empire) and then start a faction and invite them to it.

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[Astro-Boy]

There's also a decent chance that their family would take over should I die, which I am tempted to test out as that could mean a republic with 10 families but since this is an ironman save that I've grown attached to, I'd rather not