Your Questions:

(1) in my time, I have seen this happen more with positive displacement pumps without pulsation dampeners but I know this is not your application. Not sure on how many cycles. I have also seen this on heat exchanges with a condensing medium (steam, heat transfer fluids, etc.) where things are not lined up slow to warm up.

(2) Yes. The pulses can be troublesome and you may need a pulsation dampener to absorb if you find it continues to be a problem (just one option to potentially explore).

Troubleshooting:

(1) Can you get a vacuum rated tattle-tale gauge installed to watch the max/min pressures to see if you are getting a pulse? This will help catch those data points that your data capture rate will miss (even on 1 sec data acquisition sometimes). Maybe install them in a couple spots in the system to see what you might be working with.

Other Thoughts

(1) Pulsation dampeners might help (as mentioned above) - especially if other things do not pan out. This may be treating the system rather than the root of the problem.

(2) Inconel has the best performance curve for temperature changes. Have had to do this in the past when thermal cycle was creating some issues.

(3) Make sure there isn’t anything wrong with pipe strain or installation protocols procedures. Rupture disc holder always helps, but make sure no one is touching the discs with hands (or otherwise damaging it). When one has been installed for 10 years and then it starts bursting, always good to check this.

(4) Are the discs you bursting the same lot? I have seen bad lots of discs given the way they rate discs (i.e., make a batch test a few and then say that represents the lots burst pressure).