We have observed that Associations have been appearing on Deals, Companies, and Contacts where they should not be. Upon investigation, we found that within the Settings, under the Activities Object, there is an Association tab that manages the associations for each Object and Activity. It was here that we identified some incorrect settings, which were the root cause of these unintended associations. I had to manually review and update each setting, which was quite time-consuming.
I would like to propose the idea that the default settings might be contributing to the issues we faced, which now require manual correction. It might be beneficial to consider setting all defaults to "None," allowing users to tailor their settings according to the specific needs of their organization. In our situation, if we hadn't made these corrections, it could have significantly impacted our reporting and Dashboards, where these associations are utilized.