[It might be the sanctions, it might be the domestic political opposition in Belarus, it might be an updated assessment of the military situation, or the combination. Lukashenko has been running Belarus for over 30 years, and his first priority is likely Lukashenko.]
“I thought Putin owned the securitate in Belarus, and Lukashenko was his marionette.”
Could be by now, but Lukashenko was in charge in Belarus about five years before Putin came to power in Russia, so he is something of his own man.
The Belarussian Securitate may have the option to back away from an impending disaster, that the Russians don’t, because they have an alternative to Putin to fall back on, in Lukashenko.
Perhaps Intelligence or Diplomatic channels, or Belarus’ own Military, are bringing them information of a likely escalation or collapse, that would take Belarus with it, if they don’t get out of the line of fire. Could be some insider selling, or rats fleeing a sinking ship.
Maybe it is the Belarussian Securitate prioritizing their own post-war survival, rather than (or in collaboration with) Lukashenko.