The getblocks message is normal an prints in everyone's debug. To be honest it should be under debug not general. I've made note of it.
The ERROR mempool message can be solved by shutting the daemon down and restarting. If that doesn't work, try it with a -rescan option. Let me know if neither of those helped.
Yes, sometimes its normal, but not in this case, see - there are same blocks requested by same clients, its repeated constantly, with very high speed.
And start blocks are 136263 and 136762 - they are in far past already.
In normal life i've never seen same requests with any other altcoins.
Yesterday already tryed restart pool wallet, doesnt helped with mempool error. Will try with rescan later.