Based on this https://developer.android.com/studio/build/build-variants document you want this type of hierarchy structure of your application. Remove assets.srcDirs from all build flavours and you can try with this kind of structure.
***Like :*** [Flavor Image][1], [AndroidManiFest file][2]

buildTypes { release { // ... the usual stuff here } releaseAlt { // .. the usual stuff here too like signing config etc... } }
file hierarchy You should have like :
project/ - app/ - src/ - main/ - assets/ - logo.png // Generic assets go here - java/ - res/ - ... - flavor1/ - assets/ - logo.png // Specific assets for all the flavor1 Variants - release/ - assets/ - logo.png // Specific assets for all the releaseAlt Variants. - flavor1Release/ - assets/ - logo.png // very specific assets for the flavor1ReleaseAlt Variant - SDK/

[1]: http://prntscr.com/jmd7hm [2]: https://prnt.sc/jmek8w

Based on this https://developer.android.com/studio/build/build-variants document you want this type of hierarchy structure of your application. Remove `assets.srcDirs` from all build flavours and you can try with this kind of structure.
buildTypes { release { // ... the usual stuff here } releaseAlt { // .. the usual stuff here too like signing config etc... } }
file hierarchy You should have like :
project/ - app/ - src/ - main/ - assets/ - logo.png // Generic assets go here - java/ - res/ - ... - flavor1/ - assets/ - logo.png // Specific assets for all the flavor1 Variants - release/ - assets/ - logo.png // Specific assets for all the releaseAlt Variants. - flavor1Release/ - assets/ - logo.png // very specific assets for the flavor1ReleaseAlt Variant - SDK/