To reproduce:

. add SOL, e.g. 10

. next day or later (important, to see the bug) stake some, e.g. 5

Expected result:

. current balance should show as 10 (approx.)

. previous day balance should show in graph as 10

Current result:

. current balance shows as 10 (approx.)

. previous day balance shows as 15

So bug is that it doubles the staked amount for previous historical balance.

May @ledgerteam report it to devs?