Issue with Quartus Prime PRO for Stratix 10 when using a string type in a VHDL project.

Hi, Motivated by your message here and your willingness to help, I spent the last night preparing a code showing the problem. I enclose it at the end of this message. The code doesn't make any sense, but it's rather compliant with the VHDL standard and compiles correctly for MAX10 and Cyclone_IV FPGA chips. But when I choose Stratix 10 (and also Cyclone 10, which I discovered yesterday) Quartus Prime shows errors. if there is: set_global_assignment -name ENABLE_STATE_MACHINE_INFERENCE ON I get exception error: "Sorry! The Quartus Prime software quit unexpectedly." if there is: set_global_assignment -name ENABLE_STATE_MACHINE_INFERENCE OFF I get processing errors: Error(13076): The node "instance_1|str_1[1][0]" has multiple drivers. Error(20073): "constant GND" is one of the multiple drivers. Error(20073): "non-tri-state driver "str_1[1][0]"" is one of the multiple drivers. Error(13076): The node "instance_1|str_1[1][1]" has multiple drivers. Error(20073): "constant GND" is one of the multiple drivers. Error(20073): "non-tri-state driver "str_1[1][1]"" is one of the multiple drivers. Error(13076): The node "instance_1|str_1[1][2]" has multiple drivers. Error(20073): "constant GND" is one of the multiple drivers. Error(20073): "non-tri-state driver "str_1[1][2]"" is one of the multiple drivers. Error(13076): The node "instance_1|str_1[1][3]" has multiple drivers. Error(20073): "constant GND" is one of the multiple drivers. Error(20073): "non-tri-state driver "str_1[1][3]"" is one of the multiple drivers. Error: Failed to synthesize partition As you can see, the errors say that "str_1" has multiple drivers but there is only one explicit place where "str_1" is driven. The command: str_1:="ABCD";. These errors disappear when you do a tiny change in the code. For example, they dissappear when you comment the line "data<=vec_1(3 downto 0);". It makes no sense to me because this line does nothing with "str_1"! The errors also disappear when you change: if s2/=s1 then s2:=s1; str_1:="ABCD"; end if; to only: str_1:="ABCD"; which is completely strange to me, but I understand that the driver here becomes stronger then. Of course, the errors also disappear after changing the direction "inout" to "in" for "str_1" in entity "e2", but in my operative code I need bidirectional "str_1", and with this "inout" everything works fine for MAX10 and Cyclone_IV. And why did Quartus Prime put the GND driver in the "e2" entity, if it leads to an obvious drivers conflict? I hope that below code will help you find the cause and then create a fix. Here is the code with two entities: ###########################################################