I have done a linkage of an Activity to Lead and Opp through object refrence ( in spro>crm>transactions>settings for opportunities>define object relationship profile) . It is also reflecting there in WEB UI. But the problem is whenever we are changing the reference, we are unable to get the same reflected in Change history.
I have checked where we assign this profile to our transaction type. The "NO change history Box" is unchecked there.