Please launch link finder in Chrome mode and use the MPD detected instead of the copy paste mode.
I have not experienced dropout issues in the limited time I have been playing using Chrome mode BUT i have had one download that just crashed completely and repeated tries failed. Fetching a fresh MPD worked - suggesting a possible explanation. From extensive experience with getiPlayer I have found that one of the many streaming suppliers used by the BBC has a problem when accessed over a VPN. Most of the suppliers simply geolocate the IP so VPNs with IP exit ports geographically in the UK work fine. However some also check the IP against known exit subnets of the bigger VPN providers. Many of the BBC providers use a CISCO service to do that - so you either need an under-the-radar VPN supplier or you do as I do and have a dedicated IP in an anonymous subnet. Even so, the supplier 'bidi' does something else (I have not yet worked out what) and all attempts to download from them fail. In getiPlayer I use an 'exclude supplier' switch to avoid 'bidi'. I notice that the failed MPD was targeted at 'bidi'. That leads me to wonder if the normal copy/paste mode streams 'parts' from multiple suppliers and perhaps it is parts fetched from bidi that are the root of the issue. If so, the solution might be to recognize that a request was to 'bidi' and, if so, to get another URL to find a different supplier.
Whilst Chrome mode works in not having dropouts (even if some calls fail completely) it is problematic with iPlayer because some functionality that needs cookies will not work with the cut-down browser emulation. It would help if cookie implementation could be added to the emulation. Is that possible?
I hope that gives you food for thought. Happy to help further if needed.