This command
/fill 264 9 -27 205 1 -20 end_gateway 0 replace obsidian
yields
Data tag parsing failed: Invalid tag encountered, expected '{' as first char.
while it works when "end_gateway" is replaced with "stone".
Linked issues
Comments

This command
/fill 264 9 -27 205 1 -20 end_gateway 0 replace obsidian
yields
Data tag parsing failed: Invalid tag encountered, expected '{' as first char.
while it works when "end_gateway" is replaced with "stone".
migrated
(Unassigned)
Unconfirmed
Minecraft 15w33c
Retrieved
WAI. Per MC-61864, you cannot fill tile entities.