My general use case is listening to long audio-only files, mostly AAC in MP4 containers, at accelerated speed, but this issue seems to manifest regardless of size. As of the latest update, in order to get sound, I had to change my default from 200% back to 100%. I tried everything in between with the same issue: the playback counter ticks but no audio plays. I can re-accelerate audio during playback with the slider, but audio will drop again when seeking. It will work again if I drop playback to 100% and once again increase rate. I use an iPhone SE with iOS 10.3.3.
Some positive feedback, seeking has improved dramatically the past few versions. It's been a longstanding issue of mine, dating back to my previous device. Previously I'd want to fast-forward by 10-15 minutes by using the +60 or +30 second functions but on each press I'd have to wait for VLC to "find" the point else subsequent presses would be discarded and the time to find the spot would just increase, with the counter stuttering and otherwise freaking out. Finding took long enough to make the value of seeking questionable. Using the timeline was even worse, with the counter often never recovering and future seeks being difficult or impossible. Now seeks are much snappier, close to instant. This holds true for the latest version, even if output drops.