Today, on October 10, 2019, Mozilla is going to release Firefox 69.0.3 to fix downloads falling issue, along with it, this minor update addresses another issue that caused Firefox to prompt yahoo users to download files while checking emails, both these issues have been mentioned as fixed in the 69.0.3 release notes.

Here is what happened: Firefox users with Parental Control enabled on Windows 10 have noticed their file downloads are failing, the change Mozilla made in Firefox 69.0.2 for DNS over HTTPS rollout caused this. The company after receiving the reports from the users on the support forum, stopped the 69.0.2 rollout, investigated and resolved the issue.
Change log:
Fixed download errors for Windows 10 users with Parental Controls enabled (bug 1586228)
Fixed Yahoo mail users being prompted to download files when clicking on emails (bug 1582848)
You can check Firefox 69.0.3 version release notes here (currently not live).
Note: Mozilla has mentioned file downloads issue as unresolved in 69.0.2 release notes.
Related articles:
Ahead of DoH Rollout, Mozilla fixes Windows 10 Parental Controls detection issue in Firefox
Firefox 69.0.2 bug causes downloads to fail when Parental Controls are enabled in Windows 10