[5e OGL Sheet]Spell attack bonus is wrong

Hey, guys. I have no idea what is going on with this thing. I am running Storm King's Thunder, and I'm making all of my own assets using the physical book as a guide. In order to make Zephyros, I took a generic Cloud Giant, copied his stats over from the compendium, and made the appropriate edits, including a spellcasting ability, 12th level. Zephyros is holding the Staff of the Magi which gives a +2 bonus to spell attacks made while holding the staff. So I put +2 into global modifier. However, every time I went to cast a ranged spell attack, the roll kept saying +17 instead of +11. The game kept adding 1d20 + 5 (prof) + 4 (int) + 8 (spellatk). I kept going through the abilities and attributes tab and trying to fix this there. I found a globalmagicmod that responded to the global magic mod on the character sheet tab. I also found an attribute that is called spell_attack_mod which seems to be the same as the total spell attack modifier, but making manual changes to this doesn't seem to have any effect on the outcome of the actual roll. If I set global magic mod to a negative number, the spell attack will be a +9, which is what I did because then I only have to remember to add a +2 rather than subtract a +6. But even though this solution is reasonable, I am still baffled at as to where it is getting a +8 from when it should be a +2 from the staff of the magi. (putting other non-negative numbers including nothing seems to have a similar problem.) Does anyone know how to go about trying to fix this? I can just play like this, but I also want to know how to fix this in the future as well. Edit: I'm using the 5th edition OGL character sheet from roll20

(Editing title and shifting to the Character sheet forum.  Can easily be moved back to Bugs if it turns out to be a Roll20 problem rather than sheet problem)

Which character sheet are you using in your game? Also, check for duplicate attributes in the attributes and abilities section of the character journal, this can often cause calculation issues.

Here's is how mine is set up. I don't seem to be having any issues with simply putting a +2 in the global magic attack modifier    

Kyle G. said: Here's is how mine is set up. I don't seem to be having any issues with simply putting a +2 in the global magic attack modifier That is how mine is set up as well, with the exception that I put 17 in the spell save dc mod because I'm a goof. After changing that to 0, however, nothing has changed as far as how it is rolling the spell attacks. Everything looks the same for me when I roll, with the exception of [SPELLATK] which continues to say +8 anytime I have anything but a negative number in the spell modifier. I also tried with another cloud giant to see if anything would change, and when I did, it didn't produce the same result as before, but the result was still messed up. I think it said +6 instead of +8. Really not quite sure what is going awry. 

I just made yet another Cloud Giant, and it worked this time. Still don't know what is messed up with the other one. If anyone has any insight so I can avoid this in the future, please let me know.

So, I was making a character myself that had a staff similar to "Staff of the Magi" which I was trying to get the effect put in. If you use the Compendium, Staff of the Magi automatically adds +2 to your spell attack thanks to the "MODS:" section where you can put in commands to add AC, Spell Attack, Magic Item bonuses, all that jazz. Basically it makes it so you don't have to use global modifiers and you can actually change stats based off what is actively equipped rather then having to use the settings tab to make stuff work. I'd suggest checking that out and making sure you weren't adding global modifiers twice.