50fps playback at double speed

Recorded some footage on GH5 at 50fps in 1080p. Have a 25fps timeline however when i view the clip in the project pannel and source monitor pannel it very annoyingly plays it back a double speed for some unknown reason?

When i slow the clip by 50% once i've dropped it into my timeline it make the clip play at normal speed but with a bit of a jerky look to it. Dropping by a further 25% looks utter garbage and looks like i've tried to slow down a 25fps clip.

Has anyone got any idea as to why these 50fps clips are defaulting to being played back at double speed? Please help! It's enfuriating!!