First: do an opml export (and a backup - "experimental") of your actual podQast (via Discover -> Export)
cd ~/.local/sharemv harbour-podcast harbour-podcast.org
(You can also use a file browser to move the old directory away. After your tests you can then delete the new created harbour-podcast and move harbour-podcast.org back later to recover the old behaviour if you want - otherwise you can delete harbour-podcast.org if you do not need the old stuff)
Start podQast and select/subscribe the podcast which does not work for you. Do you still have problems?
If not: import your exported opml file.
What happens if you delete the podcast feed and get it back (via discover)?
Repot a bug
Best: Create a ticket here in gitlab and tell which podcast makes problems.