Here’s evidence of the 5-second delay in the Firefox console.
I can’t see any errors in the Firefox console, but when I try in Chrome, I sometimes get these errors.
includes.js?v=35a79b300ab5afa978cb59af0b05e059:839
PUT https://XXX/invites/show/XXX.json 502
XMLHttpRequest.send @ includes.js?v=35a79b300ab5afa978cb59af0b05e059:839
send @ vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:495
ajax @ vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:471
y @ discourse-27b1f43fa762ddf5962cd2fe315ed30d7328317e3f712317bcf73fe42f3e91e3.js:3948
(anonymous) @ vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:4309
O @ vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:4309
f @ discourse-27b1f43fa762ddf5962cd2fe315ed30d7328317e3f712317bcf73fe42f3e91e3.js:3948
submit @ discourse-27b1f43fa762ddf5962cd2fe315ed30d7328317e3f712317bcf73fe42f3e91e3.js:2926
B._run @ vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:4450
B._join @ vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:4449
B.join @ vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:4412
p @ vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:2577
(anonymous) @ vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:725
a @ vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:2481
(anonymous) @ vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:725
(anonymous) @ vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:719
_triggerAction @ discourse-27b1f43fa762ddf5962cd2fe315ed30d7328317e3f712317bcf73fe42f3e91e3.js:532
click @ discourse-27b1f43fa762ddf5962cd2fe315ed30d7328317e3f712317bcf73fe42f3e91e3.js:531
trigger @ vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:2235
r @ vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:2092
trigger @ discourse-27b1f43fa762ddf5962cd2fe315ed30d7328317e3f712317bcf73fe42f3e91e3.js:4230
r @ vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:2092
a @ discourse-27b1f43fa762ddf5962cd2fe315ed30d7328317e3f712317bcf73fe42f3e91e3.js:4234
discourse-27b1f43fa762ddf5962cd2fe315ed30d7328317e3f712317bcf73fe42f3e91e3.js:3940
SyntaxError: Unexpected token '<', "<html>
<h"... is not valid JSON
at Function.parse [as parseJSON] (<anonymous>)
at i (discourse-27b1f43fa762ddf5962cd2fe315ed30d7328317e3f712317bcf73fe42f3e91e3.js:3940:167)
at discourse-27b1f43fa762ddf5962cd2fe315ed30d7328317e3f712317bcf73fe42f3e91e3.js:2926:699
at b (vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:4291:12)
at g (vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:4289:128)
at h (vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:4287:107)
at p.invoke (vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:4377:192)
at p.flush (vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:4369:141)
at h.flush (vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:4384:207)
at B._end (vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:4448:9)
at B.end (vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:4401:240)
at B._run (vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:4450:118)
at B.run (vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:4410:13)
at d (vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:2577:23)
at u.error (discourse-27b1f43fa762ddf5962cd2fe315ed30d7328317e3f712317bcf73fe42f3e91e3.js:3948:44)
at l (vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:200:118)
at Object.fireWith [as rejectWith] (vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:201:698)
at E (vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:483:468)
at XMLHttpRequest.<anonymous> (vendor-52a227242ff3f3ca9d1116e8a9ef5c5c0470f27df70b8688420e4f4222a222ed.js:494:206)