Problems with Featured Slider on Admin Site

I am using CatchBase Pro (version 3.4) on a Production Site (https://everygoodgift.org/) and a Test Site (https://everygoodgift.org/wptest/). I created a Child Theme for each, but there is no customization happening in the child theme. I only mention it in case that is part of the problem. On each of the sites, I set up a Featured Slider on the Home Page with 5 images, and they worked well. I then reduced the file size of the images and reloaded them. On the Production Site, I assigned the new reduced images to the slider and then deleted the old larger images from the Media Library. It all went well. On the Test Site, I also loaded the new reduced images to the Media Library, but I deleted the old larger images from the Media Library while they were still assigned to the slider. I then went to Appearance > Customize> Featured Slider. However, now, instead of being able to assign the new images, I no longer get any of the options related to the slider on the left sidebar like Transition Effect, etc. I only get the “Enable Slider on” dropdown box at the top, and my choices are: Homepage / Frontpage, Entire Site, and Disabled, but I can no longer specify which images to put in the slider. I even tried looking in the database to see if I could enter the records that way. I found two rows in wp_options in the Production Database that seemed to affect things: “_transient_timeout_catchbase_featured_slider” and “_transient_catchbase_featured_slider”. The former had a number, which I don’t understand. In my case, in the Production Database it was “1458816944”. The latter had the html for a “feature-slider” section. I tried recreating these records in the Test Database, but it appears to have no effect. I tried changing the number to one of the ones in some of the other ‘%catchbase%’ options in the Test Database in a way that was parallel to what was in the Production Database. That didn’t seem to make a difference either. While it is not absolutely critical that I have this feature working on the Test Site, I would like it to work. Can you give me any help or direction? One other thing I should tell you. For a long time now, I have not been able to get the preview feature in Appearance > Customize to work on the Test Administrative Site even though it works fine on the Production Administrative Site. Instead of seeing the preview, I see a WordPress Admin login screen in the “preview area” and a message telling me that the session has expired and that I have to log in again. I have been living with this because I can get to all the options on the left sidebar. I mention it now only because my problem with the slider may be related.