Recently hopped over to Lemmy from Reddit, initially tried Boost and the web app and wasn’t super happy with the experience however after installing Singing I can happily say the experience has improved vastly. It feels more promising and premium than the actual official Reddit app!
That’s some plugin, though. Are you using that plugin?
It says “the sharing Intent should be created with the Intent.FLAG_ACTIVITY_NEW_TASK flag”. So maybe look into that?