Type Ahead Issue

I don't know if this is an issue with my client (Psql) or if it's
something I'm doing wrong but I've noticed this issue before and can't
figure it out. When I'm using the psql client, I really rely on the
tab / type ahead auto completion. When I run my command on one single
line, it works fine but when I break my line up into segments, it
doesn't understand what I'm trying to do:

ALTER TABLE meh ALTER C (if you press 'tab' after the 'c', psql knows
the only logical option is 'COLUMN'.

When I do the following, I don't get the same results:

ALTER TABLE meh
ALTER C (when I press 'tab' after 'C' to auto complete 'COLUMN', I get
the options only for 'COLLATION' or 'CONVERSION'. Why does it do this?
Am I missing something here? When the command is on one line, auto
complete works fine but when I break it up as show above in the 2nd
example, it acts like 'COLUMN' isn't even a valid option but if I
manually type the word 'COLUMN' and finish the command, it works. Why
is this acting this way?