In 2018 NTSB issued a report (https://www.ntsb.gov/investigations/AccidentReports/Reports/ASR1804.pdf https://www.ntsb.gov/investigations/AccidentReports/Repor

In 2018 NTSB issued a report (https://www.ntsb.gov/investigations/AccidentReports/Reports/ASR1804.pdf https://www.ntsb.gov/investigations/AccidentReports/Reports/...) listing 17 incidents where CVR was lost due to the recording not being turned off after the incident. And it also lists 17 more incidents where something happened in a flight and it took more than 2 hours to land so data from the incident was lost.