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Guessing based upon video from comments: https://i.imgur.com/T55Fihx.mp4

If the green/yellow shapes are comprised of a bunch of little, individual, pieces ....

The negative offset in the pattern editor may be failing to replicate these individual pieces because they fall outside the pattern tile clipping area.

To correct this....

• Select all the green and choose Object > Compound Path > Make.
• Then do the same for the yellow.

Now create your pattern the same way you have.

By creating compound shapes of all the pieces Illustrator sees the pieces as one, singular, object rather than a bunch of pieces. This means the shape won't be "clipped" if part of it is within the pattern's tile.

Guessing based upon video from comments: https://i.imgur.com/T55Fihx.mp4

If the green/yellow shapes are comprised of a bunch of little, individual, pieces ....

The negative offset in the pattern editor may be failing to replicate these individual pieces because they fall outside the pattern tile clipping area.

To correct this....

• Select all the green and choose Object > Compound Path > Make.
• Then do the same for the yellow.

Now create your pattern the same way you have.

By creating compound shapes of all the pieces, Illustrator sees the pieces as one, singular, object rather than a bunch of pieces. This means the shape won't be "clipped" as long as a part of it is within the pattern's tile.

Just going off of the thumbnail in the panel ...

... it appears like the artwork is not complete or correctly configured. It is a bit difficult to tell based merely on the thumbnail.

The tile itself should have green parts where I've drawn red, and yellow parts where I've drawn blue. The pieces need to show the entire tile so when it repeats, it "fills in" parts which may be clipped on overlap sides.

And in order for "parts" to be repeated then need at least be a but inside the tile boundaries. And easy solution, for this art, is to make the green shape and compound path, and the yellow shape a compound path. Then place them correctly within a tile.

Guessing based upon video from comments: https://i.imgur.com/T55Fihx.mp4

If the green/yellow shapes are comprised of a bunch of little, individual, pieces ....

The negative offset in the pattern editor may be failing to replicate these individual pieces because they fall outside the pattern tile clipping area.

To correct this....

• Select all the green and choose Object > Compound Path > Make.
• Then do the same for the yellow.

Now create your pattern the same way you have.

By creating compound shapes of all the pieces Illustrator sees the pieces as one, singular, object rather than a bunch of pieces. This means the shape won't be "clipped" if part of it is within the pattern's tile.

The only way I can think of this happening is if you have a white object in the pattern itself. i.e. if the pattern tile artwork has something like a background rectangle filled with white it will cover iterations of the pattern (it's impossible to tell if that's definitely the issue based on your screenshots).

You should remove any background and, if needed, apply a background as a separate fill in the Appearance Panel.

Just going off of the thumbnail in the panel ...

... it appears like the artwork is not complete or correctly configured. It is a bit difficult to tell based merely on the thumbnail.

The tile itself should have green parts where I've drawn red, and yellow parts where I've drawn blue. The pieces need to show the entire tile so when it repeats, it "fills in" parts which may be clipped on overlap sides.

And in order for "parts" to be repeated then need at least be a but inside the tile boundaries. And easy solution, for this art, is to make the green shape and compound path, and the yellow shape a compound path. Then place them correctly within a tile.