When you start up a route it takes ages to get a deasent LF, a compeditor starts up same route, after 2 weeks he has over 50% ? CI 30 vs my 80
Is your plane too small? are your prices too big for economic seating? Is he a new company with a heavy RI bonus on its first route?
If the competitor is a new airlines they get an initial ci boost and their first few routes that get opened get a substantial ri boost... Which can lead to what you'reseeing.
Also, markets share is not always a good representation of how well you stack up as cancellations, maintenance, and other things can skew the percentages.