What were the frequency, changes? As I understood it, they finished these ages ago and the Astra satellites would be stable for at least the next 10 years.
There are always frequency changes, and there always will be - and may be more now they have newer more advanced satellites available.
They have not finished - what has finished is the three old satellites have been replaced with three new satellites, that will lasy for the next dozen or so years.
Channels can change frequencies, polarisations, symbol rates, FECs, beams, and satellites all the time.
So if your system is looking at one frequency, then it will stop locking on if that frequency suddenly stop transmitting a carries signal, or changes its FEC or symbol rate.
Changing the symbol rate and FEC usually mean that the send less data per channel, meaning they can fit more channel onto that frequency.
And then they can change the actual configuration of the satellite transponder from DVBS to DVBS2 - again more efficient.