Honestly, I don't think it is temperature. The best way I found to induce reticulation is to use a very alkali developer, like Rodinal, and then plunge it into a strong stop. I believe the high pH solution swells the emulsion. You could try using 1:100 which should reduce the pH significantly or, better yet, use a different developer. The 120 is coated onto a different substrate and, perhaps, the emulsion is different also.
It is temperature related, but a higher alkalinity developer will soften & swell the emulsion more so acerbate the potential for problems. The stop bath and the fixer won't re-harden the emulsion but as long as they are at the same temperature as the developer won't cause reticulation regardless of their acidity.
I've used far softer emulsions like EFKE KB & PL25 in Rodinal at 3+100 with no reticulation using a standard Acetic acid stop bath and Hypam, and the Neopan 400 is better pre-hardened.
Ian

