The growng presence of ISIS in northeastern Hama indicates an important shift in the balance of power in northeastern Hama and southern Idlib. Hayat Tahrir al-Sham (foremrly Jabhat al-Nusra, the Syrian branch of al-Qaeda) is not able to stop the advancing ISIS force because it and its allies are mainly focused on the battle against Syrian government forces on other frontlines.
This shows that Hayat Tahrir al-Sham (HTS) is not able to conduct operations on multiple frontlines simultaneously. Another problem of HTS is the similarity of its ideology to ISIS. In this case, a large number of its local commanders and fighters do not want to fight ISIS.