r.q – args for .u.rep

q)(hopen `$":",.u.x 0)"(.u.sub[`;`];`.u `i`L)"
,(`pace;+`time`sym`date`pt`pn`ph`pd`pc`pa..
(5487;`:tplog/tplog2024.06.04)
q)

When I remove the . before the args I get no error and the data comes into the rdb but it only shows the data from when I initiated the rdb processes as opposed to getting all the data since the feed started.

If I add the . back then I get a type error.

q).u.rep .(hopen `$":",.u.x 0)"(.u.sub[`;`];`.u `i`L)"
'type
  [1]  /Users/user/hb/ht/tp/r.q:16: .u.rep:{(.[;();:;].)each x;if[null first y;:()];-11!y;system "cd ",1_-10_string first reverse y}

Why is this?