Tvheadend

I'm not sure if this is something not working as intended due to a bug, or due to a misconfiguration on my part - or just me making a wrong interpretation of what a feature does.

Last week (on the 31st of May) Canal Digitaal & TV Vlaanderen changed the Symbol Rates for 3 Transponders on Astra 3.
As a consequences all channels on these transponders stopped working, and all scheduled recordings failed as well.

The transponders with the new Symbol Rates were added automatically, because I had network discovery enabled.
They were added as new muxes, next to the existing - now outdated - muxes with the old Symbol Rates.
I got things working again by deleting the affecting channels and creating new ones from the services found on the new muxes.

At that time I was using version 4.1-1235~gd822a74

-

A few days ago, I saw that the feature 'Network Discovery' was changed so that instead of enabled or disabled, it now had the new options 'new muxes only' and 'new muxes + changed muxes'.
I installed version 4.1-2109~g189dcb6 and restored my configuration to the one I had on the 30th of May (i.e. before the changes to the 3 transponders were made)
I changed the option for Network Discovery from 'new muxes' to 'new muxes+changed muxes' and had TVHeadend rescan all muxes again.

I more or less expected/hoped that TVHeadend would update the existing muxes with the new Symbol Rate, and in doing so the affected channels would automatically work again.
However, that is not what happened. The 3 transponders were again added as a new muxes, while the old ones were kept, and the channels were still mapped to the old outdated muxes.

Am I reading to much into this feature, or should it have worked the way I wanted?