We have a set of test cases automated using UFT. The issues that we are observing recently are as follows:
1. In the same machine, one execution of the test cases passes. But at another time, it fails.
2. Or in other case, a test runs fine in one machine but then do not in another machine with same config.

Background Info: Some of the common issues observed are –
1. The application under test does a Search for an item in a list box. If it finds, it then selects that into a "Selected Items" listbox. So, in some cases it selects an item next to the item it has found to be the match.
2. We have put some explicit waits using the Wait command in the script. Suppose we had a 500 milli secs between events. UFT did not identify the objects within that time and it failed. We then made the wait to 1000 milli secs. It worked once. But then there was another instance when it was run but it failed.

Both machines are running UFT 14.00 on Windows 10 Build 15254 (v1709 "Fall Creators Update")