Hi, I have two questions 1.One of our process model looks really

@georgej To the best of my knowledge, here goes answer to your questions:

1. So far from my experience, it could be because of the invalid references (to deleted objects) hold by process model. If you didn't search the forum already, I would like to suggest to do it as we have some posts in which @Eduardo has suggested a approach to resolve the same (for instance, /search?q=OriginalPostID-98112). Infact a similar issue occured in our project once and got resolved in a similar fashion.
2. Assuming that the conditions under which the process model is being executed in both the environments are same (such as the contents of process model etc), one of the prime reasons for this could be because of the amount of data the chained nodes are operating on. For instance, let's say there is an write to data store entity smart service among the chained nodes that are present between two user input tasks. In one environment, this could have been tested with a very minimal amount of data where as in other environments you are dealing with huge or massive amount of data, where combination of few nodes like these can lead to break in chaining.

Hope the above gives an idea to some extent and let's see if any other practitioners can come up with some more valuable suggestions.

Thank you,let me do some triage based on your inputs