We deployed 30 AudioMoth in 2019. 20 were hardware version 1.0.0, 10 hardware version 1.1.0. Firmware for all was 1.2.0, configuration app 1.1.5. The AM were setup to record 1 minute every 10 minutes. While working on analyzing the data we found some strange patterns. While the 10 AM hardware version 1.1.0 showed expected patterns birds being most active at dawn and dusk, 17 of the hardware version 1.0.0 AudioMoth showed 4 peeks during the day and we found recordings of birds and other diurnal species during the night and recordings of bats during the day. Also, for those AM, the time of the first recording did not correspond to the time of deployment (the recording dates were earlier than the actual deployment date, all AM were programmed several days before deployment and stored with the switch OFF). Digging deeper, the hypothesis is that somehow the real time clock was running 4 times slower. Time stamps (both file name and metadata) showed a 10 minute recording interval, but in real time the recording interval was actually 40 min. This might actually be the same issue that was reported here (in that case the AM were programmed every 30 min but recorded every 2 hours): https://www.openacousticdevices.info/support/configuration-support/wrong-filenames-time-not-matching