Signing the forms at different dates and times won’t make any difference. By all means reprint and sign at the same time, but it shouldn’t be necessary at all.
My forms were all printed and signed over a fairly lengthy span, in that time documents and forms were revised and had to be recompleted, and of course re-signed.
I had my whole PR application package accepted and my OWP application approved. All with forms signed on different dates. If there is ever a question of why from IRCC further into processing, I’ll tell them that as they suggested in the guides, we took our time to compete the application, we stared it early, and double checked everything multiple times. Sometimes we had to re-do a form because we made a mistake, sometimes because you (IRCC) amended forms. Either way, there’s your explanation.
There’s nothing nefarious at play, and nothing to be concerned about, just because you completed forms on different days, weeks, or months. As long as they’re signed and dated (there’s a whole page dedicated to double checking signatures on the checklist), they wont care.
One of the last bits of advice they give you on guide, is to ensure that you’re using the most up to dates forms, before you submit. If for example they amended one form from the whole package, is it reasonable to expect you to reprint every form again just so the signatures match? That’d be ridiculous. They would also, you would hope, actually implicitly state that all forms submitted should be signed and dated on the same day, if it was actually a rule. They offer many direct instructions during this process, they return entire application packages for not following said instructions. Signing all forms at the same time isn’t one of them!