Weird keyframe behaviour(linear keyframes appear like bezier ones, only reopening premiere fixes it)

I have the following bug in Premiere, I dont know where this is coming from, it is really weird:

When i add keyframes to audio clips in the timeline to change their level, the keyframe type is set to linear as default, and thats what i want, it always worked like that since i started using premiere 6 years ago.

But now, linear type keyframes do have a bezier type shape, and i dont want that. I dont know why it does that, and the weirdest part is the following: if i save the project, close premiere and then reopen the program, the keyframes added before are now correctly linear types as they should be. all keyframes added in new audio parts (not in the ones with keyframes in it, they behave normally) have the weird behavior again.

See the attached screenshot for clarification: the keyframes with a linear shape where added before reopening the program, when added they also had the worng shape. The keyframe in the right audio clip was just added, the linear type is selected, but the shape isnt linear.

It also has nothing to do with the type of audio clip (audio clip from video or unique audio file, the bug appears in both cases in the same way)