I have to revise my original reply, I noticed something in the robot’s database.
Unknown robot identified by bot\* is identified using this pattern:
bot[\s_+:,\.\;\/\\\-]
It does group multiple bots based on this pattern. For example, bots wit the following names in user-agent would be put into this group:
bot_name
bot+name
bot:name
bot,name
bot.name
bot;name
bot/name
bot\name
bot-name
bot name
bot
You can try searching for bot+ or bot-, etc. in your logs. You can ignore name, that’s just to show that the pattern can be anywhere in the user-agent - beginning, middle or end.
Robots database: