Do engine oil and anti-freeze mix well?

My new engine oil container and my ready mixed anti-freeze container look very similar. (I had to get that bit cleared up).

Today I began to pour ready mixed anti-freeze into my oil filler. I very quickly noticed that the viscosity was all wrong and stopped. I reckon about an eggcup full got into the engine. I have not run the engine. I have drained the oil (cold) and removed the oil filter, I've even poured fresh oil through. I'm going to leave it to drain overnight and refill tomorrow.

Does anybody have experience of this? What harm might it do to the engine when running and heating etc.? I'm concerned that there might be some traces remaining in there and I don't want my engine to be blowing bubbles. I don't want to use engine flush

Sorry to hear about your problem. If it were my bike I would do exactly what you did. In addition I would install a new filter, fill the engine with oil then I run the engine until the radiator fan turns on. Immediately drain the oil and replace the filter. Let it drain overnight. Install a new filter. Fill the engine with oil.
This is what I would do if it were my bike. Cheaper than another engine.
Good luck!!!