Unknown ships stuck in construction queue

[eadgar]

Can someone please help me understand why there are Unknown ships stuck in my wharf's construction queue?

Screenshot:
https://i.imgur.com/ManBihR.png

I have checked all the usual suspects, but I don't understand it:
- There is a manager and a ship dealer
- The wharf has built ships before and will possibly build some again if I leave the game in SETA for hours
- The wharf has ware traders, but they don't seem to be doing anything even though there is money in the account and the allocated storage isn't full
- There are enough wares to build at least one S/M ship
- There are some restrictions for ship sales, but those were set a long time ago
- I have blueprints for all the factions I allow ship sales to and even if I was missing some they shouldn't order ships that I can't build

Cancelling the construction seems to work for a while and some normal ships get built, but eventually it fills up with Unknowns again.

Save file:
https://1drv.ms/u/s!AqHewQIE7Hj6rao0OXE ... A?e=8Vkv13

[MHDriver]

Had a similar situation when I built my latest SY and the default trade rules were no restrictions. Immediately after assigning a manager and ship trader and before I could change the rules NPC were placing ship build orders to include "unknown ships" which became stuck in the queue once I set the rules to restrict all factions. Had to delete the XL ship fab array and build a new one to get rid of them. May be other ways but that was the only thing that worked for me.

[CBJ]

I've moved this over to Tech Support so that it's more likely to be seen by the right person. Most of the required information is already there in your post, but can you just confirm that your game isn't modified?

[eadgar]

I've moved this over to Tech Support so that it's more likely to be seen by the right person. Most of the required information is already there in your post, but can you just confirm that your game isn't modified?

Confirmed, it's not modified. And I have both the Terran and Split expansions.

And I didn't see this behaviour in my previous modified playthrough - there were some unknown ships from time to time, but they never got stuck.

Will try rebuilding the fabrication bays, but I recently built another identical wharf and it has the same problems with unknown ships getting stuck for hours.