wallet_import_rescan is, potentially, not rounding values used for sendtoaddress in one of the test cases. Under normal conditions, the value is randomly picked and rounded to 8 decimal positions, however, for this specific case the value is limited to a maximum value that is not properly rounded. If that value happens to be picked, the test will fail.
I noticed this in a completely unrelated PR where the test failed: https://cirrus-ci.com/task/5467779164274688?logs=ci#L2684
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