Merging blending mode layers with masks

[tobbA]

There seems to be a bug or something when merging masked layers with blending modes on. If I merge several blending mode layers with masks on them together the blending mode gets disabled, resulting in a distorted final image. This is true whether I do a copy merged or select all layers and merge them together. The only way I've found to work around this is to apply my masks individually to each layer and individually merge them to a transparent layer beneath and reactivate the blending mode on the new layer.

Is this really supposed to happen?

Attaching an image of the layers setup I'm trying to merge to a single layer

[tobbA]

After some more experimentation I'm noticing that perhaps I've misunderstood the issue... It seems more that the merged version is very dissimilar from the non-merged one. However, the merged version is the same result I get as when I import the non-merged version into Photoshop. Exporting as PNG from Paintstorm gets the same result as merging the image within Paintstorm. But saving as JPG retains the original un-merged look from Paintstorm. I understand Photoshop handles blending modes differently from Paintstorm, but why would the image look different when I merge it inside Paintstorm or when saving as PNG?