Open Find/Replace
Set a search condition, such as AMOUNT < 1000
Click the + sign to add a second condition
The selected field in the first condition reverts to "ANY FIELD"
If you don't see this and enter the second condition, such as AMOUNT > 500, and click FIND, Quicken will now "find" every single transaction in your file, since ANY FIELD < 1000 seems to match everything.
THIS IS A BUG, please fix it.