The target value in the logs is wrong
The 18th trial shows a target of -1.826e+0. But at the bottom you can see that the actual target value is -182571.40432067157. It's wrong by several orders of magnitude.

What exactly are we looking at here? is this the value in the json file created by bayes_opt.logger.JSONLogger?
I've never had a problem with this - could you check the log file directly? my first guess is that this is just an issue in the way the values are being displayed...
The issue is that the column is truncated - it should read -1.826E+05, but the five is cut off.
I'm not sure what causes this because I'm not an expert in this package, but I've seen this before and I believe everything except the printing is working correctly. If you log to a json file you can see the correct (untruncated) target values
I also meet this issue, the default length of parameter to print is defined in the file "logger.py", and you can modify the 15 line code.
Fixed in #282?