Forward - Next operation leads to incorrect material

This is a bug report. Steps:

In "Sequences and Series", open section on Infinite Sequences
Click the "Next" button at the top.
Result: "Introduction" is presented - Expected: Section on "Infinity"
In "Introduction", click "Next". Result: "Infinite Sequences" is presented (as expected)
This time, in "Infinite Sequences", click "Next". Result: "Infinity" is presented (as expected)

UA-eMath / eMath