ChannelInfo Mixin properties are not persisted

The Universal Pixel channel settings disappear when saved.

Steps to reproduce:

1. Login to the Universal Pixel demo CMS
2. Navigate to Channels > Hippo Addon Universal Pixel Integration Support Demo Project > Channel > Settings
3. Change any of the values below universalpixel:channel
4. Click Save
5. Open Channel > Settings again

Expected: the change value is shown

Actual: all the default values are shown

The save actually removed all universal pixel properties from the channelinfo node (check http://localhost:8080/cms/console/?1&path=/hst:hst/hst:configurations/hippoaddonuniversalpixelintegrationdemo-preview/hst:workspace/hst:channel/hst:channelinfo ). Maybe the logic of saving channel info properties changed in HST platform?