Stack Plan Fails with undefined method 'to_sym'

[slyness]

Hi, I've never got this before but a particular stack just failed to generate a Plan with the following error.

The same stack is able to generate and provide change information using sfn diff

but the below happened when trying to generate the plan during sfn update

D, [2019-12-11T10:57:43.907725 #53857] DEBUG -- miasma.aws.signature4: generating signature for `"AWS4-HMAC-SHA256\n20191211T185743Z\n20191211/us-west-2/cloudformation/aws4_request\n64793ceecd27d1410795253b60b32ea5f7e503ed0844e1ea9ea397d6e6067e01"`
D, [2019-12-11T10:57:43.907762 #53857] DEBUG -- miasma.aws.hmac: signing data `"20191211"`
D, [2019-12-11T10:57:43.907787 #53857] DEBUG -- miasma.aws.hmac: using key override for signing
D, [2019-12-11T10:57:43.907823 #53857] DEBUG -- miasma.aws.hmac: signing data `"us-west-2"`
D, [2019-12-11T10:57:43.907847 #53857] DEBUG -- miasma.aws.hmac: using key override for signing
D, [2019-12-11T10:57:43.907881 #53857] DEBUG -- miasma.aws.hmac: signing data `"cloudformation"`
D, [2019-12-11T10:57:43.907905 #53857] DEBUG -- miasma.aws.hmac: using key override for signing
D, [2019-12-11T10:57:43.907939 #53857] DEBUG -- miasma.aws.hmac: signing data `"aws4_request"`
D, [2019-12-11T10:57:43.907962 #53857] DEBUG -- miasma.aws.hmac: using key override for signing
D, [2019-12-11T10:57:43.908000 #53857] DEBUG -- miasma.aws.hmac: hex signing data `"AWS4-HMAC-SHA256\n20191211T185743Z\n20191211/us-west-2/cloudformation/aws4_request\n64793ceecd27d1410795253b60b32ea5f7e503ed0844e1ea9ea397d6e6067e01"`
D, [2019-12-11T10:57:43.908038 #53857] DEBUG -- miasma.aws.signature4: generated signature `"8a3a7dbcae4cd68772bd37f2009aaa17d3f2e49f94f46aaf696c0bddf143d8de"`
D, [2019-12-11T10:57:44.540587 #53857] DEBUG -- miasma.aws.orchestration: extracting HTTP response body
D, [2019-12-11T10:57:44.956796 #53857] DEBUG -- miasma.aws.orchestration: unpacking HTTP response body using XML
[ERROR]: Unexpected error when generating plan information: NoMethodError - undefined method `to_sym' for ["interrupt", "none"]:Array
Did you mean?  to_s
               to_set
[DEBUG]: NoMethodError: undefined method `to_sym' for ["interrupt", "none"]:Array
Did you mean?  to_s
               to_set
/Users/abaer/.rvm/gems/ruby-2.6.3/gems/sfn-3.1.6/lib/sfn/planner/aws.rb:588:in `register_diff'
/Users/abaer/.rvm/gems/ruby-2.6.3/gems/sfn-3.1.6/lib/sfn/planner/aws.rb:447:in `block in run_stack_diff'
/Users/abaer/.rvm/gems/ruby-2.6.3/gems/sfn-3.1.6/lib/sfn/planner/aws.rb:446:in `each'
/Users/abaer/.rvm/gems/ruby-2.6.3/gems/sfn-3.1.6/lib/sfn/planner/aws.rb:446:in `run_stack_diff'
/Users/abaer/.rvm/gems/ruby-2.6.3/gems/sfn-3.1.6/lib/sfn/planner/aws.rb:374:in `plan_stack'
/Users/abaer/.rvm/gems/ruby-2.6.3/gems/sfn-3.1.6/lib/sfn/planner/aws.rb:252:in `generate_plan'
/Users/abaer/.rvm/gems/ruby-2.6.3/gems/sfn-3.1.6/lib/sfn/command/update.rb:98:in `execute!'
/Users/abaer/.rvm/gems/ruby-2.6.3/gems/sfn-3.1.6/bin/sfn:52:in `block (4 levels) in <top (required)>'
/Users/abaer/.rvm/gems/ruby-2.6.3/gems/bogo-cli-0.2.18/lib/bogo-cli/setup.rb:26:in `block in bogo_cli_run'
/Users/abaer/.rvm/gems/ruby-2.6.3/gems/slop-3.6.0/lib/slop.rb:260:in `parse!'
/Users/abaer/.rvm/gems/ruby-2.6.3/gems/slop-3.6.0/lib/slop.rb:235:in `parse!'
/Users/abaer/.rvm/gems/ruby-2.6.3/gems/slop-3.6.0/lib/slop.rb:65:in `parse!'
/Users/abaer/.rvm/gems/ruby-2.6.3/gems/slop-3.6.0/lib/slop.rb:54:in `parse'
/Users/abaer/.rvm/gems/ruby-2.6.3/gems/bogo-cli-0.2.18/lib/bogo-cli/setup.rb:50:in `define'
/Users/abaer/.rvm/gems/ruby-2.6.3/gems/sfn-3.1.6/bin/sfn:14:in `<top (required)>'
/Users/abaer/.rvm/gems/ruby-2.6.3/bin/sfn:23:in `load'
/Users/abaer/.rvm/gems/ruby-2.6.3/bin/sfn:23:in `<main>'
/Users/abaer/.rvm/gems/ruby-2.6.3/bin/ruby_executable_hooks:24:in `eval'
/Users/abaer/.rvm/gems/ruby-2.6.3/bin/ruby_executable_hooks:24:in `<main>'
[Sfn]: Continue with stack update? (Y/N): 

[gramosbr]

+1