Created attachment 68195 [details]
Tag 008 position 06 always generate be "b" and position 7-10 and 11-14 in marc field 008 are blank too.
Created attachment 68196 [details]
Image of tag 008
I've just tested this and 008 pos. 6 can be changed using the plugin. On editing again the correct value is shown etc. No problems found.