I hate when monthly manga pulls shit like this. The whole 'let's do a flashback after a cliffhanger for a fight' thing works alright for a weekly series; it's a bit annoying at times, but I get that it's meant to build a little more hype. For me though, when it happens in a monthly series, it's nothing but obnoxious, and immediately makes me begin to lose interest in what was left to 'hang' previously. All momentum is brought to a halt by the large amount of time in between. Especially when the 'interuption' could be done in a page or two instead, because of how shallow it is.
This is just 25.1, though... Maybe .2 will include the fight. Although, I also find the new trend of authors/publisher breaking up chapters into '.1' and '.2' annoying. -_-