No fill comes out as yellow fill on Adobe Illustrator

You may have inadvertently assigned a fill at the layer level, can happen very easily. Select the item, then In appearance click on the work layer

Can you show your Appearance panel?

It is possible to have multiple fills for an object (one of them may be none and selected).

If you look closely there are two anchors shown. An active one which is related to the selected no fill/black stroke object and an unselected one which is probably associated with the yellow filled object. As suggested can you show the Layer panel (expanded) so we can make sure?

Which version of Illustrator are you using?

Please elaborate and describe the issue as detailed as possible.

Otherwise it is nearly impossible to provide some reasonable advice.

How many Layers in your file?  It could be you are looking at your Layer that is currently slected and shows no fill and your non-selected Layer has the Yellow.  Just a hunch.