Not sure if this is the REASON that upgrade to 8.3.0.3 is failing, but...
The matrix you refer to (https://www.ibm.com/support/pages/node/690527?mhsrc=ibmsearch_a&mhq=spectrum%20virtualize%20upgrade%20planning) says that the MINIMUM PTF/firmware is 8.3.1.0 for V7000 Gen2. (276-AF6 is actually a V7000 Gen2+.) 8.3.0 is basically deprecated, and should not be installed on any Storwize systems. 8.3.0 codestream has not had an update in over 2 years, and is replaced with 8.3.1.x.
Recommended version, per matrix, is 8.3.1.6.
#Storwize#Support#SupportMigration