Suite project -> Transaction install -> error if suite installer includes msi x64 package

[rkarpilo]

Hello
I'm on Installshield 2015 and have a suite project which installs 2 msi packages as a single transaction. That worked fine while both msi packages were x86. After one the msi packages became x64, installer has broken - 

It is able to successfully install x64 msi, but can't install x86 msi with error:

MSI parcel launch result: 80070652

Together with the error,  2 (!) msi logs are generated simultaneously and maybe that clarifies error code 80070652  (Another installation is already in progress. Complete that installation before proceeding with this install. )

Attached msi1_1.log, msi1_2.log, debuglog1.txt are the logs for the case described. 

When the issue occurred I was on IS 2015 SP1, so I upgraded IS to 2015 SP2. Unpleasant surprise is that now behavior is even worse than with SP1. Now it is not possible to install any of the packages - neither x64 nor x86, the error from log is below, full log is attached in debuglog2.txt

Engine: error 8007007f while running parcel operations

Of course, I tried several target machines, all of them have windows installer 5.0 installed.

I performed more tests on this and figured out:

IS 2015 SP1

- Transaction, both msi packages are x64  - installation passed successfully

- non Transaction install of msi packages of any type - passed successfully

IS 2015 SP2

- Transaction, both msi packages are x64  - installation fails, error is the same 8007007f  (debuglog3.txt)

- non Transaction install of msi packages of any type - passed successfully

Any advice or suggestions on the issue will be really appreciated. Thanks!