I am very sorry about the issue. I am not entirely sure what could be causing this. Is maybe the entry itself very long? When the issue happens, does it help if you switch to another entry and then back? Or else does it help if you quit the app and open it again?
To help diagnose the CPU issue, it would be very useful to get an activity sample from Findings when it happens. For this, you’ll need to open the application called ‘Activity Monitor’, which you will find in /Applications/Utilities. In the search box, type ‘Findings’ and you should have just one row showing the activity of the app. Select the row, click on the cog wheel icon in the toolbar, and select the ‘Sample process’ item in the popup menu. The sampling will begin immediately, and you will then need to quickly go back to Findings and do whatever is needed to trigger the intense CPU usage. The sampling takes about 5-10 seconds. You can choose to ‘Save’ the sample and then you can send it to me in reply to this email. It would be probably useful to have 2 or 3 of those samples to be sure.
Thanks for your patience and help diagnosing the issue!