Yes, I installed it originally and received the errors. I then disabled, deleted the folder from addons, restarted godot, deleted the downloaded and redownloaded and reinstalled. I still received the same errors. If it helps any this is from the console.
SCRIPT ERROR: Invalid call. Nonexistent function 'process' in base 'Nil'.
at: _process_update (res://addons/assetplacer/assetplacer_plugin.gd:201)
GDScript backtrace (most recent call first):
[0] _process_update (res://addons/assetplacer/assetplacer_plugin.gd:201)
[1] _process (res://addons/assetplacer/utils/contextless_plugin.gd:66)
SCRIPT ERROR: Invalid call. Nonexistent function 'process' in base 'Nil'.
at: _process_update (res://addons/assetplacer/assetplacer_plugin.gd:201)
GDScript backtrace (most recent call first):
[0] _process_update (res://addons/assetplacer/assetplacer_plugin.gd:201)
[1] _process (res://addons/assetplacer/utils/contextless_plugin.gd:66)
SCRIPT ERROR: Invalid call. Nonexistent function 'process' in base 'Nil'.
at: _process_update (res://addons/assetplacer/assetplacer_plugin.gd:201)
GDScript backtrace (most recent call first):
[0] _process_update (res://addons/assetplacer/assetplacer_plugin.gd:201)
[1] _process (res://addons/assetplacer/utils/contextless_plugin.gd:66)
SCRIPT ERROR: Invalid call. Nonexistent function '_cleanup' in base 'Nil'.
at: cleanup (res://addons/assetplacer/viewport_3d_controllers/asset_palette_controller.gd:48)
GDScript backtrace (most recent call first):
[0] cleanup (res://addons/assetplacer/viewport_3d_controllers/asset_palette_controller.gd:48)
[1] _cleanup (res://addons/assetplacer/assetplacer_plugin.gd:154)
[2] _exit_tree (res://addons/assetplacer/utils/contextless_plugin.gd:32)
SCRIPT ERROR: Invalid call. Nonexistent function 'cleanup' in base 'Nil'.
at: _cleanup (res://addons/assetplacer/assetplacer_plugin.gd:157)
GDScript backtrace (most recent call first):
[0] _cleanup (res://addons/assetplacer/assetplacer_plugin.gd:157)
[1] _exit_tree (res://addons/assetplacer/utils/contextless_plugin.gd:32)