Blocks that connect such as chests, fences, iron bars, etc. don't connect to other blocks that they're suppose to (or of the same block). I have provided an example picture. Please note that updating the block only works until they are updated again. You cannot walk between them (example: between two glass panes), but can still interact with blocks behind them (example: hitting a dragon egg between glass panes).
Note: This only happens on servers that support multiple versions, but I don't know for sure because I can't find any 1.13 only servers.
Note 2: They work normally on realms
Thank you for your report!
However, this issue has been closed as Invalid.
Your game, launcher or server is modified.
If you can reproduce the issue in a vanilla environment, please recreate the issue.
Any non-standard client/server/launcher build needs to be taken up with the appropriate team, not Mojang.
Any plugin issues need to be addressed to the creator of the plugin or resource pack.
If you have problems on large servers, such as The Hive and Hypixel, please contact them first as they run modified server software.
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