diff --git a/app/components/autocomplete/at_mention/at_mention.tsx b/app/components/autocomplete/at_mention/at_mention.tsx
index 206839c50..697c68b8a 100644
--- a/app/components/autocomplete/at_mention/at_mention.tsx
+++ b/app/components/autocomplete/at_mention/at_mention.tsx
@@ -42,7 +42,7 @@ const getMatchTermForAtMention = (() => {
     return (value: string, isSearch: boolean) => {
         if (value !== lastValue || isSearch !== lastIsSearch) {
             const regex = isSearch ? AT_MENTION_SEARCH_REGEX : AT_MENTION_REGEX;
-            let term = value;
+            let term = value.toLowerCase();
             if (term.startsWith('from: @') || term.startsWith('from:@')) {
                 term = term.replace('@', '');
             }
diff --git a/app/constants/autocomplete.ts b/app/constants/autocomplete.ts
index 1a696ffec..d62a48d42 100644
--- a/app/constants/autocomplete.ts
+++ b/app/constants/autocomplete.ts
@@ -5,13 +5,13 @@ export const AT_MENTION_REGEX = /\B(@([^@\r\n]*))$/i;
 
 export const AT_MENTION_REGEX_GLOBAL = /\B(@([^@\r\n]*))/gi;
 
-export const AT_MENTION_SEARCH_REGEX = /\bfrom:\s*(\S*)$/i;
+export const AT_MENTION_SEARCH_REGEX = /\bfrom:\s*([^\r\n]*)$/i;
 
 export const CHANNEL_MENTION_REGEX = /\B(~([^~\r\n]*))$/i;
 
 export const CHANNEL_MENTION_REGEX_DELAYED = /\B(~([^~\r\n]{2,}))$/i;
 
-export const CHANNEL_MENTION_SEARCH_REGEX = /\b(?:in|channel):\s*(\S*)$/i;
+export const CHANNEL_MENTION_SEARCH_REGEX = /\b(?:in|channel):\s*([^\r\n]*)$/i;
 
 export const DATE_MENTION_SEARCH_REGEX = /\b(?:on|before|after):\s*(\S*)$/i;
 
diff --git a/app/screens/home/search/results/post_results.tsx b/app/screens/home/search/results/post_results.tsx
index a98125878..e61bf55ba 100644
--- a/app/screens/home/search/results/post_results.tsx
+++ b/app/screens/home/search/results/post_results.tsx
@@ -69,7 +69,7 @@ const PostResults = ({
                 const hasPhrases = (/"([^"]*)"/).test(searchValue || '');
                 let searchPatterns: SearchPattern[] | undefined;
                 if (matches && !hasPhrases) {
-                    searchPatterns = matches?.[key].map(convertSearchTermToRegex);
+                    searchPatterns = matches?.[key]?.map(convertSearchTermToRegex);
                 } else {
                     searchPatterns = parseSearchTerms(searchValue).map(convertSearchTermToRegex).sort((a, b) => {
                         return b.term.length - a.term.length;