Consider whitelisting related, singular, and plural forms of essential keywords.
On rare occasions, algorithms can negate search terms that impact good-performing keywords.
For example, the negative algorithms may negate "spatula-turner" (with a hyphen) with 100 clicks with 0 orders.
However, this may stop traffic from going to performing keywords such as "spatula turner" (without a hyphen).
A possible solution is to whitelist keywords like "spatula-turner" so that it doesn't get negated and ends up impacting essential keywords.