weird opening tracking URL error

I did a small campaign and nothing was coming up in the stats. so i looked at the HTML code for the opening tracking, and it was this:

<img src=3D"
YidzIEppbSBSYXlzdG9uCTQ0NwkJMTUxCW9wZW4Jbm8Jbm8=3D&url=3D" alt=3D"LM Openin=
g" height=3D"1" width=3D"1" />

Note how its got '3D' added to every field, 3D being the hex for "=" of course. Any idea what has gone on here? Why the "=" followed by the hex version ?
And I am getting this again today ... how do I reset this so I can get a proper opening tracking link? The links I am getting are malformed and serve no purpose. I have tried exiting MaxBulk and restarting but the links are still like that.
oh this is really weird .... link from today looks the same but I am actually getting the opening tracking through no problem. So the HTML I have shown above is valid??

But 2nd email of day ..... opening tracking just dies again, nothing at all. So I guess that is what is going wrong. First email of day tracking works, second email it doesn't.