I understand how the pool works, it has to tune to a balance between number of shares reported and bandwidth. It looks like ckpool is steering to once ever 2 seconds or so. Starting with 10000 isn't that bad, and for a high performing miner that's probably too low, for a low powered miner that's too high, but it's a good middle ground. For a BitAxe it takes between 1-2 minutes to find an acceptable share.

To not accept a suggested difficulty from a miner I can understand, and is not mandatory for a pool. However, if the pool suggests a lower difficulty, it's weird that it doesn't accept this new difficulty until about 40 seconds after this message. In the stratum protocol it states: "The miner should begin enforcing the new difficulty on the next job received.", but switching to the lower difficulty at that point first will result in several shares accepted with 'Above target'. Or I'm missing something in the protocol, that could also be the case.