diff --git a/DESCRIPTION b/DESCRIPTION
index b634d97b..c9317338 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: report
 Type: Package
 Title: Automated Reporting of Results and Statistical Models
-Version: 0.6.1.2
+Version: 0.6.1.3
 Authors@R:
     c(person(given = "Dominique",
              family = "Makowski",
diff --git a/NEWS.md b/NEWS.md
index 2becfea3..9643d141 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -2,6 +2,7 @@
 
 Bug fixes
 
+* Added regression tests for `reformulate()` formula edge cases to prevent future issues (#391)
 * Fixed issue with missing effect size for the Intercept term in type 3 anova tables (#451)
 
 # report 0.6.1
diff --git a/tests/testthat/test-report.lm.R b/tests/testthat/test-report.lm.R
index 12a64552..5e99fd7c 100644
--- a/tests/testthat/test-report.lm.R
+++ b/tests/testthat/test-report.lm.R
@@ -39,3 +39,46 @@ test_that("report.lm - lm intercept-only", {
   out <- suppressWarnings(report(model_io, verbose = FALSE))
   expect_snapshot(variant = "windows", out)
 })
+
+
+test_that("report.lm - reformulate formula edge cases", {
+  # Test various reformulate scenarios to prevent regression of issue #391
+  
+  # Test 1: Simple reformulate case  
+  model_reform <- lm(reformulate(c("wt", "hp"), "mpg"), data = mtcars)
+  result_reform <- report(model_reform)
+  expect_s3_class(result_reform, "report")
+  expect_true(any(grepl("wt", as.character(result_reform))))
+  expect_true(any(grepl("hp", as.character(result_reform))))
+  
+  # Test 2: Reformulate with formula() wrapper (exact issue case)
+  model_formula <- lm(formula(reformulate(c("wt", "hp"), "mpg")), data = mtcars)
+  result_formula <- report(model_formula)
+  expect_s3_class(result_formula, "report")
+  expect_true(any(grepl("wt", as.character(result_formula))))
+  expect_true(any(grepl("hp", as.character(result_formula))))
+  
+  # Test 3: Reformulate with interaction terms
+  model_interact <- lm(reformulate(c("wt", "hp", "wt:hp"), "mpg"), data = mtcars)
+  result_interact <- report(model_interact)
+  expect_s3_class(result_interact, "report")
+  expect_true(any(grepl("wt", as.character(result_interact))))
+  expect_true(any(grepl("hp", as.character(result_interact))))
+  
+  # Test 4: Reformulate without intercept
+  model_no_int <- lm(reformulate(c("wt", "hp"), "mpg", intercept = FALSE), data = mtcars)
+  result_no_int <- report(model_no_int)
+  expect_s3_class(result_no_int, "report")
+  expect_true(any(grepl("wt", as.character(result_no_int))))
+  expect_true(any(grepl("hp", as.character(result_no_int))))
+  
+  # Test 5: Verify format_formula works correctly with reformulate
+  formatted_reform <- format_formula(model_reform)
+  formatted_normal <- format_formula(lm(mpg ~ wt + hp, data = mtcars))
+  expect_equal(formatted_reform, formatted_normal)
+  
+  # Test 6: Verify report_model works correctly with reformulate  
+  model_report_reform <- report_model(model_reform)
+  model_report_normal <- report_model(lm(mpg ~ wt + hp, data = mtcars))
+  expect_equal(as.character(model_report_reform), as.character(model_report_normal))
+})