That just looks wrong. Why are all your files no longer than a minute in length? ( yeah I know you can set the interval, but 1min seems odd) Plus even though they all look like they are a minute or less, the files sizes are all over the place. My little VioFo uses MP4 file format, set to 3 minute time slices and all the files are the same size, give or take 1-2KB. Advice that came with camera was to format the card before use and to format it at intervals after that. (or are the files from 2015! the ones that work?)
I'd format the card first as it costs nowt, failing that try a different card, Dashcams are quite hard on cards anyway so you should be using something halfway decent. (Sandisk Ultra's are known to be problematic)
https://www.youtube.com/watch?v=3QAF2flNsVc
Might be worth checking to see if there are any firmware updates for the camera itself.