With hundred of posts being written every hour, I believe 1 post per week shouldn't be considered "bumping"... and debates like those are why I wished there was a reason-field when a post is deleted.
Updates considered as bumps. Posts without questions, discusssion, replies from others considered as updates as I understand.
By the way, is there an official rule regarding merging new and old posts together or is this your personal suggestion as a good practice to behold?
If your posts merged by moderators, I am sure that merged ones look very messy. Once again, moderators don't have time to merge your posts with full details (they have to add details manually), ie. days of posts/updates. I have my posts merged, so I know it. My decision is delete merged posts after all.
In fact, I am OP and I even don't feel reasons to spend my time to add details into merged posts. After my update posts deleted and merged, I read rules again. Then I felt moderators did right things that is another reason forced me to delete my merged posts.
The forum, admins, and moderators must not handle all things in the forum. Admins have their right to shut down the forum anytime they want or disable signature anytime too. It is a painful and undeniable fact that signature is one of the root causes of shitposts. I don't say OP made shitposts and deleted by moderators but I want to emphasize that most of deleted posts are shitposts.
Each admin or moderator has different ways to interpret the forum rules (unofficial) so there are some inconsistencies between moderators but most of times they are right with their interpretations and judgments.
23. When deciding if a user has broken the rules, the staff have the right to follow their interpretation of the rules.[e]
Sometimes moderators leave a note with PMs to posters with reasons why posts delete or merged (I got some) but it is not a must-do thing for moderators when they handle reports.
In April or May, when thousands of accounts banned, people created topics and asked links to posts that cause their bans. Moderators (hilariousandco, I remembered) replied that they don't have time to do this. I think the answer to OP is nearly the same.