So if you are using global mouse click center it means that you are using region mode for the OK button. What i saw from the first is that form behind it had some different values, so region mode will look for the image first of the main screen i would suggest to use coordinates option on this case instead of image search in the region mode. If you use image search on the main screen every time you go to it will be different.
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Ramon Nunez
Customer Solutions Engineer
Blue Prism Software Inc
UTC
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