OK, this appears to rule out any problem in the communication path or your browser plugins. Now a few questions to narrow down the problem (or problems) so I can try duplicating.
First, to confirm: you're observing the same thing (initial content being discarded instead of being appended to when you edit after first creating) for both entries and comments? For instance, when you first create an entry or comment with about 90 characters, then edit that entry or comment and add some extra text at the end, that extra text ends up replacing the original text instead of being appended to it, like "foo(imagine 87 more characters)bar" becoming just "bar"?
Second, for entries, are you using the old update page on that server or the new "beta" one? You can check by looking at https://www.example.org/beta where "example.org" is the domain name of your server install.
Third, do you have Javascript disabled (for your server or in general) in the browsers you've tested this with?
Fourth, can you check (using bin/ljdb or bin/dev/entrydump.pl) whether the damaged content is actually stored in the database?
no subject
First, to confirm: you're observing the same thing (initial content being discarded instead of being appended to when you edit after first creating) for both entries and comments? For instance, when you first create an entry or comment with about 90 characters, then edit that entry or comment and add some extra text at the end, that extra text ends up replacing the original text instead of being appended to it, like "foo(imagine 87 more characters)bar" becoming just "bar"?
Second, for entries, are you using the old update page on that server or the new "beta" one? You can check by looking at https://www.example.org/beta where "example.org" is the domain name of your server install.
Third, do you have Javascript disabled (for your server or in general) in the browsers you've tested this with?
Fourth, can you check (using bin/ljdb or bin/dev/entrydump.pl) whether the damaged content is actually stored in the database?