It needed 1Mb, if you didnt have 1Mb contiguous chunk of memory you will get an error. The error was in the channel allocation which is done on the target database
Not yet. The 1.5 is still larger than what the error is complaining about and it is on the target, not the catalog, and the errors says it's a RPC error, which makes it look like the catalog is the problem. Have you seen something like this to make you think it is actually the target?