How can I prevent Telegram from starting automatically on Debian 8.7 Jessie?

I'm using Telegram Desktop on Debian 8.7. It starts automatically even though I've not created any .desktop file under ~/.kde/Autostart. It's quite annoying as I don't want its window to show up maximised but I'd rather start it with the --startintray flag. I've also tried to create the .desktop file under the Autostart folder but that seems to not override this weird behaviour. By opening the running services I can see why this occurs (why telegram opens by itself), I get the following hint when I go over "Telegram" with the cursor: