[v1.2.1](20fe) Cannot build destroyers despite having tech

[runyond]

I have the engineering tech for both destroyers and destroyer assembly yards and yet cannot build destroyers. This bug was just plain weird and has kinda messed up my game significantly.
Relevant screenshots and save file are attached.

Steps to verify:
Click on my capital spaceport (Level IV)
Look at buildable ships and notice destroyers are not listed
Click on "researched" on the technologies tab to verify I have the correct techs and note that I am currently researching cruisers, the next possible ship type and thus should be able to build destroyers

Any help in explaining what is going on? I don't think this is a widespread issue, but probably a minor coding error that can be easily fixed in the next patch. I, however, do not code and have no idea how this happened.

 

[Zemurin]

A destroyer design did not autogenerate (bug?). Happened to me sometimes. Go to ship designer and see if you can make one manually, then build it.

 

[runyond]

That worked! Thanks. No idea why the design didn't autogenerate. That's clearly a bug and one that would really mess over newbies to the ship designer mechanic.

 

[ForzaA]

Thank you for your report.

I've added the bug to our database, but without a hint of why it failed to auto-design, I'm afraid it's unlikely to be fixable. Keeping our eyes out for any clues as to what may be causing this, of course.

Just eliminating the obvious-but-unlikely ; you didn't delete or overwrite the destroyer design by accident?

 

[Zemurin]

Would it be possible if this happened if the new ship class design was autonamed as an existing design and in the end does not end up created due to conflict?

A longshot but this happens to me very rarely across vanilla and heavily modded games, and it is very difficult to reproduce, or even realise it happened sometimes for months after researching a new ship class.

 

[ForzaA]

Would it be possible if this happened if the new ship class design was autonamed as an existing design and in the end does not end up created due to conflict?

A longshot but this happens to me very rarely across vanilla and heavily modded games, and it is very difficult to reproduce, or even realise it happened sometimes for months after researching a new ship class.

As far as I can determine, they don't overwrite/preempt designs in other ship classes - it's possible to have a corvette and cruiser design both of the same class name.