The tooltip of Regeneration cores says that slotting multiple mods will cause the healing effect to stack. This is true.
BUT
The game will only heal you based on the last gear piece you equipped. Ie. if you have 2 r9 mods slotted in primary (190 Hp each for 380 total) and 1 r5 slotted in secondary (126 Hp) and you slotted/equipped this one last, you will only be healed for 126 Hp every 3 seconds instead of 506.
Unequipping and re-equipping the gear mid combat seems to fix that issue and the game properly heals you for the correct total amount, but you have to do this each and every time you go into combat.
Plz->Fix
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