I would argue that a combination of profit-taking and intervention fears is what is contributing to the latest descend in USD/JPY today. The idea that 145.00 could be the level where Japan steps in to intervene in the currency market is so far enough to put off traders from chasing a much higher move after the gains since mid-June.
USD/JPY daily chart
Of note, the drop back under 144.00 today puts sellers back in control in the near-term but I would expect buyers to hold some ground ahead of the US non-farm payrolls tomorrow.
But there is a pocket of space between 140.00 and 144.00 now that could lend itself to a sharper retracement, so just be mindful of that.
For today, there are also large option expiries for the pair at 144.00. So, that could keep price action thereabouts before rolling off.