Hi,
do you remember the pybot issue placing only 0.5 NBT in buy-sell walls although much more funds exist?
The last days since BTC value changes all the time, pybot tries to match BTC value in order to place sell-buy orders.
That is the place-time where those errors appear. If pybot restarts (manually or aytomatically) the error dissappears until the new recalculation and placing of the orders.
I hope the pybot people to pinpoint and correct the bug.