boltTLDR
Google has removed the requirement to block internal search results from indexing, but continued blocking remains advisable to avoid server load and quality issues.
In the latest Search Off the Record podcast, Google's John Mueller clarified that blocking internal search result pages is no longer mandated in Google Search Essentials, per SERoundtable's reporting. However, Mueller noted that sites should likely continue the practice anyway, as indexing such pages can trigger intense server load and quality problems that ultimately hurt search rankings—making the de facto recommendation unchanged even if the formal guideline shifted.