Matrix.org@buckket the IRC bridges run by matrix.org preserve IRC history semantics (i.e. you can't see history from before you joined), unless the chanops explicitly special-case the channel to share history. If you're seeing anything else it's a bug or a regression. Please DM us the channel you're talking about so we can investigate.
Jonkman Microblog is a social network, courtesy of SOBAC Microcomputer Services. It runs on GNU social, version 1.2.0-beta5, available under the GNU Affero General Public License.
All Jonkman Microblog content and data are available under the Creative Commons Attribution 3.0 license.