Thank you for your post.
How many records are visible in List View. If you have more records than can fit on the screen, then after sorting, you will remain in the current record, but it may not be the first record in the sorted list. See if you can scroll upwards. You may want to change the button to execute a script that not only sorts by the field but then includes the script step:
Go to Record/Request/Page [ First ]
This ensures you will be at the first record of the sorted set.
Let me know if you need additional clarification or continue to run into difficulty.
The number of records all fit on the screen, so it is not a screen overflow/scrolling issue.
It will have 7 lines showing. Perform sort. Then only 4 showing.
I am unable to replicate the issue. If the found set of records is changing from 7 to 4, there must be another action taken than just Sort and Go to Record/Request/Page [First]. I'd like to see your file so I can determine why this is happening. Check your Inbox at the top of this page for instructions where to send the file.