Displaying sometimes wrong?

[mahbgithub]

Hi,
I use the a2s a lot in dokuwiki but frequently get some issues:

                                                                           #------------------#
                                                                   #-------+  Echo 1          |
                                                                   |       #------------------#
                                                                   |
          #-------------#                #------------------#      |       #------------------#
          |     Hello   +----------------+     World        +------+-------#  Echo 2          |
          #-------------#                #------------------#      |       #------------------#
                                                                   |       
                                                                   |       #------------------#
                                                                   +-------+  Echo 3          |
                                                                           #------------------#
                                                                           
     |
     |
 ----#-----
     |
     |
     |  
                                                                              
     |
     |
 ----+-----
     |
     |
     | 
     
     |
     |
 ----o-----
     |
     |
     |           
</a2s>

Surprisingly the upper and lower crossings are displayed differently. Any idea wha?
Best reagrds
Martin