[1][2] The airing of the first episode was postponed from its originally scheduled premiere date of February 26, 2021, on KBS2, in light of emerging school time bullying allegations against the lead actress, Park Hye-su.

[16] On October 12, 2020, Kim Sae-ron left the series due to a row over the cast billing order.

[18] The series is entirely pre-produced with filming scheduled to be completed in early February for the production team to focus on post-production and music editing.

The release of Dear.M was indefinitely postponed due to a controversy involving school violence allegations against Park Hye-su.

In May 2022, the Japanese streaming platform, U-NEXT announced in a press release that they would be exclusively distributing Dear.M starting in late June 2022.

[24] On February 24, KBS canceled the broadcast program as actor Park Hye-soo, who plays Majua, was embroiled in controversy over school violence.