Delta Liepard is unobtainable (Bug)

So,I had gone to the wiki and done the steps to encounter delta liepard and when I went into the battle (I had finished most of the post game)I encountered cresselia and now delta liepard isn’t spawning.

just spawn an egg for it then

3 questions:

Have you tried softreseting?

Does Cresselia always replace Delta Liepard?

Want me to trade you a Delta Purrloin?