There has been a bug in the app for months now, where if you listen to a podcast episode, sometimes the point at which you pause the episode is not preserved between devices, or even when returning on the same device. For example, if you pause 30 minutes in on a podcast on your phone, and switch to listen on your PC a day later, Spotify will not remember where you left off, and will restart the episode.
This isn't the only bug. Spotify also will sometimes, completely randomly, switch episodes for the same podcast. Example: You are listening to episode 100, and during the middle of the episode, it will randomly swap to a completely different episode. My assumption is that this is related to the script that runs to interrupt an episode with advertisements. Instead of playing an ad, it will play a new episode.