My green tea brews brown, not pale
A green tea that should pour pale yellow-green comes out amber or brown, even brewed cool and brief.
Likely cause
Alkaline water is the common cause: it is what pushes a green tea's colour from pale toward brown.
Test it at your sink
Squeeze lemon into the brewed cup. If the colour drops back sharply toward pale yellow, pH was driving it, which points at your water rather than your leaf.
What to change
Brew the same leaf with filtered or bottled low-mineral water; a paler cup points at your tap water.
The chemistry behind it
A green tea gone brown is not over-steeped: alkaline tap water pushes the colour from pale to brown, so your tea is being bullied by the local water board.