In version 2019.1 was is implemented a development which allows supporting of custom properties by all entities. This development required a significant change of the code behind the functionality.
This reflected the Available Products panel, which is more specific and required further adjustments. As a result, the custom properties that are already shown in the Available Products panel and are saved in the view will disappear after the upgrade to 2019.1. Therefore, it may be necessary to re-add those properties in views.
There currently is no data about other affected panels or issues with views.