There are loyalty issues in the Ukrainian military, that are sure to complicate issues should they come to blows with Russia. Many units will defect to Russia, and many will not have the stomach to fight (Especially those from the East).
Pravda is suggesting loyalty issues, but they are not in widespread evidence even in the Crimea, which is majority Russian (as opposed to merely Russian-speaking). Ukrainian military units in the Crimea remain under central government control. They're not fighting probably under strict government orders because they'd be annihilated since they are (1) behind enemy lines, (2) outgunned and (3) outnumbered. They remain in the Crimea as symbols of Ukraine's continued claim to the territory. The majority ethnic Ukrainians in the east might lean one way or another vis-a-vis foreign relations, but just as Russian-speaking Israelis are ultimately loyal to Israel, even if they might favor Russia in the foreign policy realm, Russian-speaking Ukrainians should have few issues as regards their allegiance to the Ukrainian state. Note that Pravda's assertion that the entire Ukrainian Navy had defected to Russia was wrong.