t/deferred.t started to fail (with newest Dancer2?)

On my smoker systems:

#   Failed test 'to /fake'
#   at t/deferred.t line 82.
#                   '/fake?dpdid=85419182'
#     doesn't match '(?^:^http://localhost/fake)'

#   Failed test 'to /show'
#   at t/deferred.t line 92.
#                   '/show?dpdid=85419182'
#     doesn't match '(?^:^http://localhost/show)'

#   Failed test 'message set and returned'
#   at t/deferred.t line 100.
#                   'message: 
# '
#     doesn't match '(?^ms:^message: goodbye)'
# Looks like you failed 3 tests of 9.
t/deferred.t ........... 
Dubious, test returned 3 (wstat 768, 0x300)
Failed 3/9 subtests

Statistical analysis suggests that the failure happens with Dancer2 0.300003:

****************************************************************
Regression 'mod:Dancer2'
****************************************************************
Name                   Theta          StdErr     T-stat
[0='const']           1.0000          0.0000    39354018391671128.00
[1='eq_0.205000']         0.0000          0.0000       3.45
[2='eq_0.205001']         0.0000          0.0000       3.28
[3='eq_0.205002']         0.0000          0.0000       2.73
[4='eq_0.206000']         0.0000          0.0000       8.56
[5='eq_0.207000']         0.0000          0.0000       0.00
[6='eq_0.300000']        -0.0000          0.0000      -2.76
[7='eq_0.300003']        -1.0000          0.0000    -37262909289529656.00

R^2= 1.000, N= 122, K= 8
****************************************************************

With Dancer2-Plugin-Deferred-0.008000 it may fail differently:

# Failed test 'message set and returned'
# at t/deferred.t line 100.
# +---------------------------------+----+---------------------------------+
# | GOT                             | OP | CHECK                           |
# +---------------------------------+----+---------------------------------+
# | <!DOCTYPE html>\n               | =~ | (?^ms:^message: goodbye)        |
# | <html lang="en">\n              |    |                                 |
# | <head>\n                        |    |                                 |
# |   <meta charset="UTF-8">\n      |    |                                 |
# |   <meta name="viewport" content |    |                                 |
# | ="width=device-width, initial-s |    |                                 |
# | cale=1.0, user-scalable=yes">\n |    |                                 |
# |   <title>Error 404 - Not Found< |    |                                 |
# | /title>\n                       |    |                                 |
# |   <link rel="stylesheet" href=" |    |                                 |
# | http://localhosthttp/css/error. |    |                                 |
# | css">\n                         |    |                                 |
# | </head>\n                       |    |                                 |
# | <body>\n                        |    |                                 |
# | <h1>Error 404 - Not Found</h1>\ |    |                                 |
# | n                               |    |                                 |
# | <div id="content">\n            |    |                                 |
# | //localhost/show\n              |    |                                 |
# | </div>\n                        |    |                                 |
# | <div id="footer">\n             |    |                                 |
# | Powered by <a href="http://perl |    |                                 |
# | dancer.org/">Dancer2</a> 0.2080 |    |                                 |
# | 01\n                            |    |                                 |
# | </div>\n                        |    |                                 |
# | </body>\n                       |    |                                 |
# | </html>\n                       |    |                                 |
# +---------------------------------+----+---------------------------------+
# Seeded srand with seed '20200513' from local date.
t/deferred.t ........... 
Dubious, test returned 1 (wstat 256, 0x100)
Failed 1/9 subtests

This seems to happen with older Dancer2. Statistical analysis:

****************************************************************
Regression 'mod:Dancer2'
****************************************************************
Name                   Theta          StdErr     T-stat
[0='const']           0.0000          0.0000       0.00
[1='eq_0.204004']         0.0000          0.0000       0.00
[2='eq_0.207000']         0.0000          0.0000       0.00
[3='eq_0.208001']         0.0000          0.0000       0.00
[4='eq_0.300000']         0.0000          0.0000       0.00
[5='eq_0.300003']         1.0000          0.0000    164322117824390912.00

R^2= 1.000, N= 83, K= 6
****************************************************************

PerlDancer / dancer2-plugin-deferred

t/deferred.t started to fail (with newest Dancer2?) #12