Jump in trace plot w/ new chain

Some of the parameters in my model show a big jump in the trace plot between the end of the first chain and the start of the second. Any underlying reasons for this jump out at anybody without having to paste in my entire model (fairly large)?

In the example chart attached I’m running 1000 draws w/ 2 chains. You can see there’s stark level shift right at the 1000th draw.

trace.Jump