So Mystery Pattern does not work on 10 amulet summons.

[IchigoMait]

If you scroll to the left side on the main screen and choose help, and then choose mystery pattern.
"【Mystery Pattern-May】

Mystery Pattern： Heart
Instruction:
Every month refreshes mystery pattern.
Draw the pattern for the 1st time every month to obtain Mystery Amulet*1
Receive the amulet only when triggered the pattern(it will show on the screen after summoning)

(not available for 10x-amulet summon)
"
lol that it's still displaying may there, while june is soon ending.