Pixhawk Hexacopter sudden raise in height

I am newbie to drone so kindly give the solution in detail and step by step procedure to solve the issue.
Pixhawk drone flies normally in stabilize mode but if I change the mode to loiter, alt hold, position hold there will be sudden raise in height. I tried with all the firmware no use. Even checked all the connection and it was perfect and less vibrations produced… so overcome vibrations I installed Anti vibration mount to the pixhawk… But issue did not solved

You need to post a link to a .bin flight log.

You could also take the preventive measure of doing a step by step methodic tuning as explained in the Blog post.
And if the problem precissts, post a log.