meta-miner error while switching

[tinsami1]

I have 3 cpu miners encounter this after a few hours of mining:

!!! Ignoring job with new algo cn/1 from the pool (10.77.77.120:1111) since we still waiting for new miner to start
[2018-08-20 15:12:09] : Fast-connecting to localhost:3333 pool ...
[2018-08-20 15:12:09] : Pool localhost:3333 connected. Logging in...
>>> Pool (10.77.77.120:1111) <-> miner link was established due to new miner connection
!!! No pool (10.77.77.120:1111) job to send to the miner!
!!! Pool (10.77.77.120:1111) <-> miner link was broken due to closed miner socket
[2018-08-20 15:12:19] : SOCKET ERROR - [localhost:3333] CALL error: Timeout while waiting for a reply
[2018-08-20 15:12:49] : Fast-connecting to localhost:3333 pool ...
[2018-08-20 15:12:49] : Pool localhost:3333 connected. Logging in...
>>> Pool (10.77.77.120:1111) <-> miner link was established due to new miner connection
!!! No pool (10.77.77.120:1111) job to send to the miner!
/home/xmr/mm.js:361
        err("[INTERNAL ERROR] Can not update pool (" + c.pools[pool_num] + ") job since its first job is missing");
                                                               ^

ReferenceError: pool_num is not defined
    at pool_new_msg (/home/xmr/mm.js:361:64)
    at Socket.<anonymous> (/home/xmr/mm.js:273:23)
    at emitOne (events.js:77:13)
    at Socket.emit (events.js:169:7)
    at readableAddChunk (_stream_readable.js:146:16)
    at Socket.Readable.push (_stream_readable.js:110:10)
    at TCP.onread (net.js:523:20)

All miners where using self-compiled xmr-stak (for zero dev fee). They were all mining cn-lite and this error happened when they tried to switch to cn/1