Trying to chain together two sail form, and I'm not able to get the previous

On the first form, did you go to the "other" tab in the node configuration and select the checkbox to "Allow users to step back to this node from the next chained activity."?

Yes...
- emabled chaining between the two nodes.
- checked the "Allow user to step back" in the Other tab.
- And am using a very simple sail form for both nodes (see below).

=load(
local!priority,
a!formLayout(
label: "Loan",
firstColumnContents: {
a!sectionLayout(
label: "Input ",
firstColumnContents: {
                     a!buttonLayout(
                              primaryButtons: {
                               a!buttonWidgetSubmit(
                                        label: "Submit",
                                        value: null,
                                        saveInto: local!priority
                               )
                              }
                     )
                    }
)
}
)
)

Are there any nodes in-between the two user input task nodes?

Nope. I tried to make it as easy as possible just to see it work. I created a quick mock-up on Friday for the client using Portal forms and all worked perfectly. Not sure how Sail would have changed things, seeing how all configuration setting are within the process model.

Please try:
=load(
local!priority,
a!formLayout(
label: "Loan",
firstColumnContents: {
a!sectionLayout(
label: "Input ",
firstColumnContents: {
}
)
},
buttons:
a!buttonLayout(
primaryButtons: {
a!buttonWidgetSubmit(
label: "Submit",
value: null,
saveInto: local!priority
)
}
)
)
)

Steve, You're a genius for catching that. Thanks a million!