Yes.
More specifically but missing 90% of the twists and turns, so apologies if the sequence isn't perfect:
The USSR supported the Democratic Republic of Afghanistan/ People's Democratic Party of Afghanistan, a marxist-leninist faction, which formed around 1965. Infighting between moderates (Parcham), who wanted common cause with other leftists, and extremists (Khalq), who wanted military revolution, ensued, with the Khalq group, led by Hafizullah Amin, coming to leadership and Parchams in many cases expelled to the USSR/Eastern Bloc. The Soviet Union supported/bankrolled anti-Amin efforts (he was killed in 1979 in a bloody Soviet-backed palace coup; this was Yuri Andropov's work, and Amin had been poisoned on Soviet direction previously; they also tried to kill him via sniper) and installed someone from the pro-Soviet Parcham (Karmal). Back in power, the Parchams claimed they were in the national-democratic stage of Marxism (they later moved toward Afghani nationalism). In 1979 the USSR combined with the pro-Soviet Afghani (Parcham) government against the mujahideen insurrectionists.
So yes, they have supported Marxist efforts all over the place. The soviet-afghan war was considered a proxy war btw the US and the USSR, representing self-determination/ democracy (or at least any alternative to Marxist or communist power) vs USSR/marxism/communism. Conflicts in Africa were often similarly proxied conflicts.