Question about the entropy loss

using the Stock_NeurIPS2018_SB3.ipynb notebook , default parameters
the results seems to be ok
but after checking the tensorboard log , I found something confused
1. Why the entropy loss is negative and keep gowing?
2. The train/reward indicate the agent not learning something useful ?
3. After checking the actions of the agents action on the trade dataset , the actions almost the same , buy some shares and keep holding....