Workflow fails randomly, error handling question.

We have a flow that is supposed to create some tasks on specific HR service cases and it seems to fail randomly and I don't know why. I would like to add an error handler to the flow that can send me an email with the reason why. 

In the email body, are data pill items added there, they will be in the text of the body correct?

Is there any other way to figure out why a flow may or may not have just decided not to start or finish? I looked at the event logs for errors but it doesn't seem to capture the flow issues.

Its very random but like one day it is fine, another it isn't. One day half the cases work and the others dont and I see no correlations between any of the cases that work/don't work that lead me to what is happening.

how do other people deal with this type of flow situation?