SYMPTOM
Allowing personal answer to be remembered vi the "Remember this answer" option doesn’t work for child prompt in the prompt-in-prompt structure in Strategy Web.
Follow the steps below to reproduce the issue in Tutorial project:
1. Follow KB5490 to create a prompt-in-prompt using attribute Year and Month, so Year is the parent prompt and Month is the child prompt.
2. For both prompts, set "Personal answers allowed" to Single.

3. Include the prompt in a report and execute it.
For Year, choose an answer, e.g 2015, and check “Remember this answer”.

For Month, choose an answer,e.g. May 2015 and check “Remember this answer”.

4. Re-execute the report.
For Year, the previous selected element is remembered as expected.

But for Month, the previous selected element is missing.

CAUSE
This is known behavior for a child prompt in the prompt-in-prompt structure in Strategy Web.
WORKAROUND
Use the Personal View functionality instead. See KB40298.
ACTION
Our Technology team has reviewed this behavior, and it is not scoped for any upcoming scheduled Strategy release.
The Strategy Internal Reference Number for the issue discussed in this technical note is DE117855 and KB442164.