CTD bug has something to do with 1944 DDs!!

[Wulfmann]

When I got to December 1943 my flawless up to then patrols encountered a CTD. I put in a different RND and still CTD but now I noticed it was when I came within range of an escort. I restarted and when I got to a convoy I could see the merchant ships but when I turned my peri on the escort, CTD.
I restarted and came across a lone DD on patrol and when I came close enough, even though it was dark as soon as I turned the peri in that direction CTD.
I thought maybe the later US DD Fletcher (I have seem Clemson and Somers) or DE Butler and Buckley (I had seen Evarts) so I put them in a mission and they loaded OK in that with a 1944 date.
The SCR patrol would indicated it was a Brit DD there and the North South convoys would have Brit DDs there.
Is there any ordinance added in December of 43 that might cause a conflict problem? Would a sonar mod change something in Dec 43 and on? If I avoid any DD I can run the patrol and get back to base. Only if I register a visual. The hydrophones can hear them and not crash but if I let it show on the peri it is CTD.
Any ideas? This does not seem like it will only be my problem. Other will run into this and it must be a mod conflict but what. I don't have many mods in this install yet but I do have the sonar fixes!
Wulfmann