I too have seen strange behavior regarding log file names.
Yesterday Logsearch said it was rejecting a log file due to a name issue, despite the name meeting the name convention {callsign} @ {reference} {date}.{extension} but the file was still accepted for upload on the QSOs were added to Logsearch.
VK port-a-log names the file as {callsign}@{reference}_{yyyymmdd}.adi
e.g. VK3ZPF@VKFF-2224_20200111.adi which, up until recently, have passed the Logsearch upload process without warning.
Please advise if the {callsign}@{reference}_{yyyymmdd}.adi is no longer acceptable.
73
Peter VK3ZPF
VK port-a-log author