Ring HDR video has lower framerate?

Hello, Since about a week I own a Ring Door View Cam, and besides the audio problems I have with timeline event viewer and my Samsung Note9 (see other posts, this affect all users with modern Samsung phones and the Android app with timeline event viewer feature on) I'm very happy with my device! One thing I noticed today I wanted to ask the community, and/or tech-support: When using the HDR video feature turned on, it seems to me that the framerate of the video is lower then without HDR. The videos look like mich more "choppier", and I estimate the framerate between 7-10 fps. The video is still encoded with 15 fps, but the real fps seem to be lower when compared to a NON-HDR recording. Can it be that HDR combines two frames to one, the get the HDR effect? Therefore reducing the real fps to ~7-8? It seems to me that the NON-HDR videos look better, because of the higher fps... Does anybody have some information in regard to that? Thank you and best regards from Vienna, Markus