[GAMEPLAY] Manamune "mana charge" passive still active on Muramana

So, I was recently playing around with dual tear Ryze in a practice game. After charging up Muramana using auto-attacks on a target dummy and fast-forward, I was going to charge archangel's the same way, since my auto attacks now spend Mana. But, I noticed I wasn't getting 8 charges per attack like I expected, but only 5. Basically, when Manamune gets upgraded to Muramana, it loses the mana charge passive... But really it's still there! And, since I was hitting the CD of mana charge, the 5 charge per auto-attack was hitting first, using up all the mana charge CDs, and slowing done the gain.

Confirmed by waiting till I had more CDs available on mana charge. First auto-attack gained 13 charges. 8 for the archangel passive, and 5 for the Manamune passive I no longer have.

Edit: also, auto-refresh CDs does make the mana-charge CD appear to disappear, when it shows up on the item. But, ultimately, it does not increase the rate of charging at all. Would all be much easier if Ryze would continue auto-attacking when I fast-forward :(