Threading problem Haas SL10 lathe

I've been having a problem turning threads on our Haas SL-10 CNC lathe. The thread is a 1.460-40TPI, cutting with an LT16-ER AG60 insert which is rated from 48-8 tpi. Thread depth is .024. The threads are just not coming out right out all. I am turning almost the same tpi in a .995 ID bore which is coming out perfectly. I've attached a photo of the threads in question. You can clearly see these are some cowabunga threads and look like waves. They do not fit in the mating hole well at all. I've tried several different speeds and feeds combo, some having a better or worse finish but almost all turning over the crest of the thread like this. Here is a sample of the code that I'm using
N24 G92 X1.4504 Z-0.2485 F0.025
N26 X1.4408 Z-0.2487 F0.025
N28 X1.4312 Z-0.2489 F0.025
N30 X1.4216 Z-0.249 F0.025
N32 X1.412 Z-0.2492 F0.025

I've tried this at anywhere from 150-5000rpm, constant or reduced x step distance, radial infeed, 2-5 degree flanked infeed.... Nothing is really working. The most frustrating thing is these threads were cutting well earlier this week! Nothing has happened to the machine (crashes,etc) that I know if.

I'd really appreciate any tips!

-Chris

Attachment 252802

You mentioned trying different speed and feed combo's. Your code doesn't show the RPM, but would only have 40 TPI @ 1000 RPM. I suppose that would only affect the TPI, and not the appearance however. If you can find a backup copy of the program, see what combo was working earlier in the week. If it looks any better running it twice, maybe it's the depth of cut, and more passes would help.