ln case this may be helpful to someone down the track: I had the same issue, and it was caused by lack of disc space on the C-drive where the reload log history log files are stored.
The task logs in the QMC are shown only of last 30 days.
You can check the "Governance Dashboard" (if configured) for the info about the historical tasks.
Also, you can enable the document log for individual qvws in top menu bar - Settings --> Document Properties --> General Tab --> Enable(Check/Tick) Generate Logfile and/or Timestamp in LogFile Name
