Since wp 4.5. 4.5.1 Adding additional subdomain causes problems

This issue occurs since wordpress update to 4.5. and still exists in version 4.5.1

Adding a subdomain automatically reset an existing multisite domain e.g. https://stationary.dealsmarthosting.com to ://stationary.dealsmarthosting.com and makes a site inaccessible.

Modifying ://stationary.dealsmarthosting.com this wrong site pointer to https://stationary.dealsmarthosting.com to gain site access again is so far impossible.

All indicates that the problem which causes this situation is done by the fact that new subsite resets the installation to a wordpress single site installation.

Appreciate much any advice/help to get this fixed shortly.
In advance thank you.