您可以使用:tabclose（缩短的别名也适用于:tabc）。
阅读更多关于:help tabpage的信息。
至于用:bn返回的缓冲区，我相信这对“隐藏缓冲区”来说是正常的，当你经过最后一个缓冲区时，:bn会绕到第一个缓冲区。
请参阅:help buffer-hidden

你把标签和缓冲区弄混了。标签只是显示缓冲区的一种方式，关闭它不会对它们做任何事情。
如果要从缓冲区列表中删除缓冲区，请使用:bd。在帮助中：

:[N]bd[elete][!]            *:bd* *:bdel* *:bdelete* *E516*
:bd[elete][!] [N]
        Unload buffer [N] (default: current buffer) and delete it from
        the buffer list.  If the buffer was changed, this fails,
        unless when [!] is specified, in which case changes are lost.
        The file remains unaffected.  Any windows for this buffer are
        closed.  If buffer [N] is the current buffer, another buffer
        will be displayed instead.  This is the most recent entry in
        the jump list that points into a loaded buffer.
        Actually, the buffer isn't completely deleted, it is removed
        from the buffer list |unlisted-buffer| and option values,
        variables and mappings/abbreviations for the buffer are
        cleared.

:tabclose将需要与:tabN而不是:bn耦合。正如最初的答案所暗示的，制表符和缓冲区不是同一个概念。如果使用制表符，使用正确的命令将有所帮助。

如果您使用的是common vim：:bd
如果您使用的是SpaceVim之类的软件：SPC+b+d将删除当前缓冲区。