There is no way to tell which ship class the original mission designer intended.
Perhaps it was intended to be interchangeable? Fenris cruisers were supposed to become Leviathans and vice versa via quick retrofits? It sounds weird, I know, but it may be an explanation to this inconsistency. After all, these ships used to look exactly the same.
On a side note, I'm playing through these campaigns after... ages. Tango was smooth, and I'm currently playing Destiny of Peace. Eagle Takes Flight results in a crash on startup due to a mainhall setting. 337 non critical warnings are reported by FSO as I run the Port with this mod, but no other issues so far.
Also: :nervous:
Quarantined Arcadia installations before it was viral...
(https://cdn.discordapp.com/attachments/223511363807346691/778015319888887888/Immagine.png)