Yes water or coolant can get into the oil pan through the intake manifold if the intake manifold gasket is leaking.
The intake manifold has channels and passages that seal between the intake manifold and the engine to allow the water to go through the intake manifold and through the engine but should not let water or coolant into the engine itself where the oil is.
If the coolant or water gets past the intake manifold gasket it can leak into the oil where it then gets into the oil pan and cylinder.
A bad head gasket can also be another cause of the coolant or water in oil but most commonly it's caused by the intake manifold gasket leaking.
I've had coolant in my oil pan before and it turned out to be the intake manifold gaskets were leaking because of age as the gasket seal broke down.
After replacing the intake manifold gasket it stopped leaking coolant into the oil.
Water or coolant in oil is a bad thing and can cause the engine to not get lubricated properly which then leads to engine damage and bearing failure and then the engine will seize up.