From: https://spservices.codeplex.com/discussions/447851
Marc,
I have two list. There is a column called Class and another column called Start Time in a custom list (or app in 2013 terms). Another list has columns that are lookup fields to those values. The users are able to select mutiple classes (parent) and the start times available (child) are filtered based on the selections.
This process worked beautifully in 2010 and I have utilized it a few times elsewhere with no issues. Another oddity is when I do not allow multi-selections in the lookup the script works as expected. I tried using the 2013.1 library that you just published with no-luck.
If you would like any code samples I would be more than happy to provide but to be honest this is straightfoward and seems to be related to the same issue mentioned in the thread below.
http://spservices.codeplex.com/discussions/438514
Thank you very much for any assistance you can provide.
Comments: Released in 2013.02