PPT Export and History Log fields HTML Tags in 6.5
I think this is because of having more no:of vies on dashboard which doesn't fit on ppt page . Try reducing or changing layout of dashboard and try an export.
Also if there is any custom object generated View's it may get buggy.
There has been a defect filed for the PPTX issue - ARCHER-69759. At this time, the resolution date and/or Archer version has not yet been established, however; we welcome you to reach out to Archer Support at any time for an update. Additionally, we recommend review of future Release Notes, where the JIRA may be listed under Fixed Issues or Known Issues.
Regarding your second issue, history log entries for text area fields include HTML encoding (functions as designed) to prevent an XSS attack. There is an Enhancement Request to change the functionality to provide the option to show/hide HTML encoding. The Product Team came back with - "This enhancement is in line with the overall product direction. The enhancement will be considered for a future release. A specific timeline for this RFE is not available at this time."