Noticed this exception in twistd.log on ews server. This error is happenning consistently for atleast past few days (in all the logs we currently have on ews server, from 2023-01-28).

2023-02-02 06:08:55-0800 [-] Got fatal Exception on DB
        Traceback (most recent call last):
          File "/usr/local/lib64/python3.6/site-packages/twisted/python/threadpool.py", line 255, in <lambda>
            ctx, func, *args, **kw
          File "/usr/local/lib64/python3.6/site-packages/twisted/python/context.py", line 118, in callWithContext
            return self.currentContext().callWithContext(ctx, func, *args, **kw)
          File "/usr/local/lib64/python3.6/site-packages/twisted/python/context.py", line 83, in callWithContext
            return func(*args, **kw)
          File "/usr/local/lib/python3.6/site-packages/buildbot/db/pool.py", line 217, in __thd
            log.err(e, 'Got fatal Exception on DB')
        --- <exception caught here> ---
          File "/usr/local/lib/python3.6/site-packages/buildbot/db/pool.py", line 190, in __thd
            rv = callable(arg, *args, **kwargs)
          File "/usr/local/lib/python3.6/site-packages/buildbot/db/logs.py", line 155, in thdAddLog
            "log with slug '%r' already exists in this step" % (slug,)) from e
        builtins.KeyError: "log with slug ''stdio'' already exists in this step"