Miners mine on "onw chain" after fork

[febe19]

I get the following issue:
After an accidential fork, miners start mining on their own chain and do not focus on the longest chain anymore. This results in different blocks which where validated & added to different chains. This again results in different states (e.g. differetn txcount for accounts) what opens the possibility that some transactions are valid in some miners whereas in other miners they are not valid. This only occures when transactions are sent to the network.

Setup:
9 Miners (based on commit 5f4ee8a) mining with different accounts. Blocksize 500'000, Block interval 180s, Difficulty interval 20 blocks. After starting all miners, let them mine for approximately 2h so that the chain stabilizes in regards of block mining speed. Then start sending transaction on a regular basis (tested it once with 1Tx per second per miner, once with 12Tx per minute per miner and once with 6Tx per minute per miner). After a while forks and the issue start to appear.