After upgrading to 2.70, we noticed that parameters were being erased or wiped after you went into the configuration of the job to edit any information. not only is no information being saved but configuration that was previously there was cleared as well. 

i tried to edit the jobs thru the xml file locally and restart jenkins. that was fine until you go back into the configuration again, then it wipes it clean and clears it from the xml file again. we had to downgrade from 2.70 back to 2.63 to get that functionality to work again

Edit:

In general, we cannot save any configuration, not just parameters. any general config settings are getting wiped out. Discard old builds, do not allow concurrent builds, parameters, etc.