NASA did not lose all the telemetry data for the Apollo missions, but there has been some controversy and confusion over the years about the fate of certain Apollo-related data, specifically the Apollo 11 moon landing telemetry and video recordings.
The issue primarily concerns the original Apollo 11 telemetry data tapes and the high-quality SSTV (Slow Scan Television) broadcast tapes. After the Apollo 11 mission, NASA reused or disposed of many magnetic data tapes due to storage limitations and the high cost of the tapes at the time. This practice led to the loss of some original recordings, including the high-quality SSTV video footage of the moon landing.
However, it's important to note that NASA did not lose the telemetry data that tracked the spacecraft's journey to the moon and back. Much of the data related to the Apollo missions, including flight logs, scientific data, and other recordings, have been preserved and are available. The loss mainly pertains to the original high-quality video recordings of the Apollo 11 moonwalk, which were recorded over during a period when NASA was facing a shortage of magnetic tapes.
In summary, while some specific recordings, particularly the high-quality SSTV tapes of the Apollo 11 moon landing, were lost or recorded over, the broader telemetry data for the Apollo missions have been retained and are accessible.